A Lesson in Biology
Copyright© 2026 by Lubrican
Chapter 3
Coming of Age Sex Story: Chapter 3 - She wanted to be a cheerleader but her grades were too low. Summer school might solve that problem. But she needed a tutor to make sure. Her mom got a name from the school and he was hired. When they got to the biology tutoring, she wanted to understand the reproductive system. He was happy to teach her about it.
Caution: This Coming of Age Sex Story contains strong sexual content, including mt/ft mt/Fa Mult Teenagers Consensual Heterosexual Fiction Incest Mother Son Brother Sister Harem Interracial Black Male White Female First Lactation Masturbation Oral Sex Petting Pregnancy Voyeurism
Marcus had a big smile on his face. Molly felt a little foolish for asking if this teenage boy was trying to seduce her. Marcus answered the question without reluctance.
“As delightful as I’ve already told you that would be, it would also be the actions of a cad and I do not think of myself as a cad.”
“Cad is an antiquated word,” said Molly.
“My mom likes the old terms,” he said.
“And you didn’t answer the question.”
“I would love to ... but no. If you were divorced I’d be interested, but you’re waaay out of my league.”
“Not at all,” said Molly. “You’re much higher on the food chain than you think. Either that or you’re a master seducer. Have you fucked my daughter?”
“No, Ma’am, I have not.”
“If I ask her the same question will she answer it the same way, or will she blush and get nervous and avoid answering?”
“I don’t know. She’s right over there, swimming. Call her over and ask her.”
“If you haven’t done that, why would she act like I described?”
“Well, I don’t know if you would understand, but there is a cultural thing in America where some women think of black men as dangerous bad boys. And dangerous bad boys make some women’s panties damp. They have fantasies, sometimes. Not a few of them seek an actual relationship, just to find out what it would be like. They like to live dangerously, or what they think of as dangerously. My mom says I’m handsome and I work out a lot and she also says I’m buff. She has warned me not to let some white girl screw up my college plans by satisfying her curiosity to my detriment. By that, in this case, I mean the girl gets caught under her tutor and legal issues commence. So no, I have not fucked your daughter, but I also have no idea what fantasies, if any, she might have had about me, and which would embarrass her if you knew about them.”
Molly rose from her chair and went to the end of the pool. Robin was about to stop anyway, so she stood up in the shallow end.
“Has Marcus fucked you?” she asked, bluntly.
What flashed through Robin’s mind wasn’t what they had done. It was the answer to the question, which was unequivocally “no.”
“No, Mother,” she said, her voice in a high, but firm alto. “Why would you ask me something like that?”
“Have you ever had any fantasies about him?”
Now the girl blushed, and it started in the very bountiful exposure of her inner breasts and flowed up into her cheeks. It was obvious.
Molly held up her hand.
“Never mind. I had a couple just a few moments ago myself. There’s nothing wrong with you. He’s a very sexy young man.”
She turned and returned to Marcus, aware that he was watching her like a man watches a woman. She blushed, herself, when she realized she was rolling her hips intentionally.
She had barely returned to her seat when a streaming-wet Robin charged into the scene.
“What’s going on?” she asked, hotly. “Why did you say Marcus is sexy?”
Molly looked at Marcus and gave him a rueful smile.
“You’re right. She’s naïve. She should never have repeated that.”
Marcus bowed his head and kept his smile to just a slight rise of the corners of his lips.
“Mommy! You answer me right now!”
“Sit down, Darling,” said Molly. “We need to talk about some things I should have talked with you about years ago, but was too chicken to do so.”
“What?” Now Robin sounded confused.
“Just sit and listen!” snapped Molly. “And cover up. You look practically naked. It’s not nice to give your tutor a boner.”
While Robin sputtered (and did not cover up) Molly looked at Marcus.
“I’m sorry. I shouldn’t have said that. It was presumptuous.”
“We’ll just pretend the boner is your fault,” said Marcus with a smile.
“What the fuck is going on here?” yelled Robin. She was terrified that her mother had found out about the foreplay. But she was also smart enough to know her mother wasn’t acting like that was the case, her rude questions aside.
“What the fuck is going on is that I can use that word and you cannot, Robin!” said Molly, her voice hard.
“I’m sorry,” said Robin, instantly. “I’m just very confused right now.”
“Are you aware that Marcus thinks you’re beautiful and sexy?” asked Molly.
Robin was ready for this question.
“Of course he does. All boys do.”
“That’s not an attractive way to answer that question,” said Molly.
“I didn’t mean him any disrespect,” said Robin, as if Marcus wasn’t there. “He has looked at me like other boys look at me, but he doesn’t behave like other boys. I mean he’s not rude and gross about it.”
“That’s better,” said Molly. “He finds me attractive, too.”
“What?” Robin looked at Marcus.
“We’ve been having a nice conversation about men and women and perceptions and problems adults have with sexual issues,” said Marcus. “That isn’t on the lesson plan for you, but your mother was a little worried it might have been.”
“Mom,” said Robin, trying to sound droll. “Ewww.”
“Don’t ewww me, young lady,” said Molly. “You just admitted you’ve had sexual fantasies about Marcus.”
“I did not!” said Robin, hotly. “I never answered that question!”
“Your body did. If you had blushed any harder you would have looked like you had gotten a sunburn.”
“Blushing doesn’t mean anything,” said Robin, sulkily. “I mean I was surprised. I didn’t understand why you’d ask me something like that.”
“I asked you about your feelings because of the feelings your tutor caused in me during out discussion.”
“What feelings?”
“Your father is cheating on me with his intern,” said Molly, calmly. “That has left me a little vulnerable and Marcus noticed it. He said some very nice things to me and I reacted on a visceral level. I was worried that you might have responded the same way. I was only exposed to him for half an hour. You’ve been alone with him for hours and hours and hours.
“How did you find out about Daddy, anyway?” asked Robin, who obviously ignored the rest. “How can you be sure?”
“I was at a fundraiser last night for the dog shelter and the roommate of a girl who is interning with your father was talking to another girl, saying that her roomie caught her a sugar daddy. That means rich, sexual partner.”
“I know what it means, but she could have been talking about anybody.” Robin sounded like she was lecturing her mother.
“Not when said sugar daddy was named Brad Fitts,” said Molly, just as calmly.
Robins attitude changed instantly. She went to hug her mother.
“I’m so sorry, Mommy,” she said, beginning to cry. “I still don’t understand how he could he do that to you.”
“Marcus had the same reaction,” said Molly.
“Mom! Why on Earth would you tell Marcus that Daddy was cheating on you? That’s kind of private, don’t you think?”
“He’s a good listener. It just popped out.”
“She was under a lot of stress,” said Marcus. “I think it overwhelmed her and I just happened to be here when she had to say something or else break down. Don’t worry. I know this is private and I won’t say a word to anybody.”
“Thank you,” said Robin. She turned back to her mother, still trying to act like this was new information. It was ironic that she acted “dumb” for Marcus, to make sure her mother didn’t know he knew things he shouldn’t know, yet, and to make it look to her mother like she was “presenting” new information to Marcus. “You must be devastated! What are you going to do?”
“Well, I was devastated, but somehow, talking to Marcus, here, brought me a little comfort. Your father doesn’t think I’m sexy, but Marcus does.”
Robin looked at Marcus.
“Please tell me you did not tell my mother you think she’s hot.”
“I can’t help it if she is,” said Marcus, with a shrug.
“He thinks you’re hot, too, Darling,” said Molly. “And that’s what I want to talk to you about.”
“No he doesn’t,” said Robin, sounding certain. “He hasn’t done a single thing that was like he was hitting on me.”
“That’s because he’s a gentleman,” said Molly. “Other men are not, and while it’s fine that you trusted Marcus, I need to make sure you don’t trust the wrong boy ... or man ... in the future.”
“Please don’t make me stop dating,” moaned Robin.
“I know how these things go, Sweetheart,” said her mother. “Banning things never works. If I try to ban you from doing something all that will do is make you want to do it more.”
“Then what do you want?”
“I want you to talk to Marcus with me, not as his student, but as a woman. I think Marcus will agree to be truthful, no matter what we ask him, and you and I will be able to ask him questions that, hopefully, will help us understand the male of the species better. I thought I understood your father but obviously I do not. So I may be able to learn something that will help me move forward in my situation. Our situation. In a way, he would still be a tutor, just on a subject that we didn’t originally plan for him to teach.”
“What kind of questions?” asked Robin, looking from her mother to Marcus and back again. Molly looked at Marcus, who had no idea where this woman was going. He’d never been in this situation before.
“Will you answer questions we ask you truthfully, Marcus?”
“I will try,” he said.
“Why only try?”
“Because sometimes the truth is hurtful,” he said. “I do not want to hurt either of you.”
“Why not?” asked Molly, leaning forward. “Why do you care whether you hurt one of us or not?”
Marcus still didn’t have a clue as to what was on this woman’s mind, so he answered carefully.
“First, I don’t want to hurt anybody, not just you and Robin. Second, if I did, you might ban me from coming back here and that would make me sad.”
“Why would that make you sad?”
“Because I like coming here.”
“Keep going. Why do you like coming here? You’ve never spoken ten lines to me before this, not counting the interview I don’t seem to remember. Is it the money?”
“No.” He frowned. “It isn’t only the money.”
“What else could there be? Remember. Tell the truth. We need to know why you like coming here other than for the money.”
Marcus was beginning to get a glimmer of what might be going on. She had told Robin she needed to understand men and what they want. What he was thinking might be dicey, but he didn’t think so. The things he’d already said to Molly would have gotten him thrown out of most houses, especially houses of rich people. He decided to put his toe deeper in the water.
“I like coming here because I like seeing you.” He looked at Robin. “I always like being around you and now I really like being around your mother.”
“Why, Marcus?” asked Molly, softly. “What do you think about while you are talking to her ... and me?”
“Most men would not want to answer that question,” said Marcus. “Answering that could get a guy tossed out.”
“And this is where I want your education to continue, Darling,” said Molly to Robin. “Marcus? When I said I’d change out of my swimming suit you asked me not to. Is that because you like looking at my nipples and camel toe?”
It was so silent that Marcus thought they might hear his heart beating.
“Yes,” he said, softly.
“Marcus!” gasped Robin, who also had no idea what was going on but was amazed he’d answer the question.
“And do you like looking at Robin, in her bikini, this one, which shows most of her breasts?”
“Okay. Yes,” said Marcus. “But that doesn’t mean you should be afraid of me. My reaction is biological. It’s natural. Nature has set us up to be that way. Scientists say that every man evaluates every woman he sees in terms of whether he’d want to mate with her. It’s not always even a conscious thing, but women get put into categories. The same thing happens with women. Women automatically look at every male and ask the same question. Would he be the best man to mate with? Would he make strong babies? Would he provide well for her so she and her babies will flourish? Again it doesn’t always happen on a conscious level.”
“And what category are we in?” asked Molly.
Marcus swallowed. He stared at Molly.
“I don’t really want to answer that question,” he said.
“Why? Because it would hurt us? Do you think we’re hags, or stupid, or ugly?”
“You know I don’t,” said the boy.
“Then why would it hurt us to know which category you would put my daughter and myself in?”
“Because it isn’t polite to discuss this kind of thing.”
“Okay. We’ll talk about that later. Would you please take off your shirt?”
“Why?”
“Because I don’t want to categorize you without as much information as I can get. Take off your shirt. What could that hurt?”
“You want to categorize me?”
“You said it’s normal; that we all do it.”
“I also said it isn’t polite to talk about it,” he said.
“Take off your shirt, Marcus. Please.”
He looked at Robin, who had owl eyes and looked nervous.
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