A Lesson in Biology
Copyright© 2026 by Lubrican
Chapter 10
Coming of Age Sex Story: Chapter 10 - 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
The next Tuesday Marcus arrived as always, ready to tutor Robin.
“Work before anything else,” he said.
“What makes you think anything else will happen?” said Robin, trying to sound strong.
“With you? Nothing. I was thinking of trying to get your mother to skinny dip with me again.”
“You don’t have to be a butthead about it,” said Robin.
“I do if you get sassy on me,” he said with a grin.
They worked for two hours and then went to the kitchen to get a snack. Molly was wearing her reading glasses, poring over bills and balancing her checkbook. She looked up when the two youngsters approached.
“Marcus wants us to go skinny dipping with him again.”
“I don’t think so,” said Molly. “It’s too easy to float too close to each other. If we’re going to satisfy our urges I think we need to be in separate parts of the room while we do it.”
“Hmmm,” said Marcus. “I could get into that.”
“I didn’t mean it literally,” said Molly.
“Well, why not? I’d love to see you naked, across the room, making yourself happy.”
It was as they all got up and left the kitchen together, that Molly realized with a strange certainty, that she was going to let Marcus have her whenever he tried to, even if it was before she should. He had that kind of power over her. Then she thought about how much her life had changed when Marcus came into it. All of those changes were good, in her opinion. So she stopped worrying and thought about how hot what they were about to do might be.
They ended up in the den, where there were overstuffed chairs upholstered in a buckskin kind of material. It felt soft and warm when the two women sat down in one, naked. Marcus stood between them and a few feet outward.
“You two look so delicious,” he said, as he began to stroke his rod. “I can’t wait until I can touch you with this.”
He aimed his penis at each one as he jacked.
“This is so nasty,” moaned Robin. “I can’t believe I’m doing this.”
“You don’t have to do it,” said Molly, who was already breathing hard. Her clit seemed especially sensitive and she knew getting an orgasm was going to be easy. “You can go to your room and read.”
“As if,” panted Robin. “Ohhhh, I can’t believe I’m doing this in front of my mother.”
“And I can’t believe I’m doing this in front of my daughter,” groaned Molly.
“You guys are so hot. I’ve never done it with a white girl or woman. I can’t wait to get inside both of you. I’m gonna try to give you twins.”
“That is completely inappropriate to say,” gasped Molly.
“Truth and honesty,” he grunted. His hand flashed faster. “Would you let me get you pregnant?”
Again, that fuzzy fantasy in which Molly could show a mixed race child to her cheating husband as revenge, popped into her head.
‘“Maybe,” she moaned.
“Mother!” yipped Robin. “You can’t let him get you pregnant. You’re too old.”
“I’m thirty-five. I could have three more children before the onset of menopause.”
“Oh, fuck, and I’d give them to you,” gasped Marcus. “I’m sorry. I wanted to wait until you came, but this is too hot.”
Robin was on his left. He had already claimed her with the little ritual of cumming on her with her permission. He looked at Molly. She was full. She was mature. She knew what to do with a cock inside her. He wanted her so badly that if he thought about her while he jerked off he could cum in two minutes. Of course he didn’t need to masturbate. He had more than enough women who wanted his dick in their pussy, not in his hand.
Molly had laid back and slid down in the chair. Her heels were spread far apart. Her hand was a blade and the flat tip of the blade whipped back and forth, as if trying to create enough friction to start a fire on her clit.
He intended to ask if he could do it. When she leaned her head forward with wild eyes and said, “Kiss me!” he moved quickly. His right hand was busy but his left was available to support his weight as he leaned over her and sought her lips. She almost ate his lips, and her passion turned the key. His orgasm engine started and a test of the hydraulic control system in his body commenced. That test failed, as the fluid rushing through his system found an outlet.
Even squeezing his prick hard didn’t stop it. He was still jerking and when he came, the tip of his prick was pointed directly at where a cock belongs during sex. Her fingers kept flashing, but that was at the top of her slit. His essence splashed into her flushed, open lips. Some of it got into the dark channel beyond those lips. She felt it and jerked, which brought her pussy in contact with the tip of his still spurting penis.
It was instinct, really, that made him rub the tip of his prod up and down her slippery slit. He felt her grab his cock and almost brutally use it to torture her clit. She screamed, not the scream of a scared woman, but the guttural, rasping scream of a woman being overwhelmed by orgasm. She shoved the tip of his cock down and into her opening. Her inference was clear. He could fuck her if he wanted to. But he had cum hard and was already below half staff. She was able to stuff maybe an inch of his penile flesh into her opening, but it wasn’t really sexual penetration.
She was sobbing when he stood up. It stabbed into his heart and he was afraid he had scared or hurt her. He reached for her hand and pulled her up. His embrace pulled her naked body against his chest.
“I’m sorry,” he whispered into her ear. “I didn’t mean to scare you. Are you okay?”
She slid her hands to his ass and clenched. She barely made a dent and she leaned back.
“You didn’t scare me. I scared myself. I wanted you in me. I’m going to want you in me again. I won’t be able to resist you if you say you want to make love to me. I have to depend on you to make me stick to our original agreement.”
She kissed him, and it was a long, warm kiss. They were embraced by Robin, who added her body heat to theirs.
“Did he put it in you?” she panted. “You screamed and it looked like he was trying to get it in you.”
“No,” said Molly, after she broke the kiss. “He only touched me. It was ... intense. I think it was the most intense orgasm I ever had.”
“That’s awesome. I was almost there, but then you screamed and it scared me a little. I didn’t get to cum.”
Marcus looked into Molly’s eyes.
“Can I help her out?”
“Just don’t do what you did to me.”
“I can’t. I’m still soft.”
“Then help her. I’m going to go soak in the tub. I think I’m done for the day.”
It would have been better if Molly had stayed and monitored the two teens. Marcus got Robin in the same chair her mother had been in and draped her knees over his shoulders. Then he sucked her clit until she also let out a guttural yell. He shrugged her legs off of his shoulders and they lay, limp. When he got to his knees she was wide open in front of him.
And he was hard again.
He didn’t fuck her, but he may as well have. While he sucked her nipples he jerked off again. And when he felt it rise he rubbed the tip of his prick up and down her steaming slit. When he came, the first jet pushed against skin and spurted in all directions. He adjusted and the tip dipped into her vaginal opening. He didn’t push in, but when his second, third, and fourth shots went off they went directly into her birth channel.
“I feel something hot and wet!” she cried.
“That’s just me, breaking the rules,” he panted. “You need to go sit on the pot. I got some of my spunk up inside you.”
“It felt like you put a hose up in me,” she said. “My whole pussy feels warm and wet.”
“Go let it drain out of you. Maybe that will be good enough. Where is your calendar?”
“I haven’t made one, yet,” she panted. “Wow, but that felt good. If real sex feels better than that I’m not sure I’ll stay conscious to enjoy it.”
Marcus knew she’d stay conscious the whole time. He also knew she’d cum just as easily as his sisters did. And Molly? Molly would cum before he even got it all the way in her.
And now he wanted to do that much, much sooner than waiting until he graduated high school.
He talked to his mother about it the next morning, before she went to work. He told her he was going to have to stop going over there and that it gave him a physical pain in the middle of his chest. Delores gave him a hug and kiss and told him to hang on while she thought about things. What she did was call Molly and arrange to meet with her for coffee between her jobs. That meant waiting until two in the afternoon, after she worked 6 hours as a maid at the Best Western Motel on the highway through town. At three she would go to her second job, which was washing dishes at Henry’s Steak House. That establishment only served lunch and dinner, but dinner was their rush period and the kitchen was crazy between seven and eleven.
Molly suggested that Delores just come to the house and they could have coffee there.
Normally, Delores would have turned down such an invitation, assuming she even got one from someone of such disparate social rank. But she didn’t see Molly as a rich, white woman. Well, she did, but she also saw her as a friend. That, in itself was still a little difficult to take in, but she believed it.
When Delores parked, Molly was waiting at the front door.
“What’s wrong?” she asked, immediately after exchanged a brief hug.
“Why does something have to be wrong? Can’t I just have coffee with my new white friend?”
“Of course you can, but I don’t buy it. I don’t know you all that well, but I don’t believe you’d just happen to want to have coffee with me between jobs, just for the heck of it.”
“Okay. There is a problem, but I have no idea what to do about it.”
The coffee was already brewed and after they sat down at the kitchen table, Delores just told her what Marcus had said.
“It seems my foolish son has fallen head over heels in lust with both of you,” she said.
“Do you really think it’s just lust?”
“Isn’t that all you want it to be?”
“I’ll be honest with you. I’m having a hard time deciding what I want, other than a divorce. That much is rock solid. But when it comes to Marcus, I might be in lust with him, too.”
“A woman your age, with your mind, doesn’t fall in lust with a teenage boy,” said Delores.
“Then what is it?”
“You’re lonely. Your husband is an ass. My son may be an idiot but he’s a thoughtful, gentle, sexy idiot and since I respond to that, I’m not surprised you respond to it, too. My suggestion is for you to get on some birth control pronto.”
“Well, that’s not helping either of us resist this,” Molly grumped.
“Do you really want to resist? And if you do, could I ask why?”
“Yes, you can ask why. You know that song where the chorus says, ‘you just make me feel like a natural woman?’ It’s like that. When I’m around him I just turn to goo. He makes me feel like a woman. The problem is he makes me feel like I should be a woman in every aspect of life. I told you about that stupid fantasy I have about delivering a brown baby just to stick it to my husband. And that’s a terrible thing to fantasize about. It’s not that I think it would be terrible to shake up my husband. But I shouldn’t want to create life with a man I like so much just to get revenge. If I’m going to have Marcus’s baby it should be because I just want to have his baby.”
Delores leaned back in her chair and stared at the woman across the table. Maybe she was just crazy. A lot of white women were.
“Can I ask this question?” Delores said. “Why on Earth would you even think about wanting my boy to father his child on you?”
To read the complete story you need to be logged in:
Log In or
Register for a Free account
(Why register?)
* Allows you 3 stories to read in 24 hours.