A Lesson in Biology
Copyright© 2026 by Lubrican
Chapter 16
Coming of Age Sex Story: Chapter 16 - 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 looked up at Molly as she rode him. She did it differently than his mother did. Molly braced herself with her hands on his chest and then made her loins go in circles. Every four or five circuits she would rise almost off of his erection and then let her body weight slam her back down. It looked like a lot of work to him.
“Can I ask you a question?” he asked.
“Why would you want to ask me a question while we’re doing this?” she panted.
“We can do this any time you want to,” he said.
“I want to right now!”
He waited until she whined she was cumming and pulled her down to lie on his chest. Her big, pale breasts felt soft in a way that nothing else felt soft.
“Doesn’t it hurt your breasts to lie on them like that?” he asked.
She lifted her head and looked at him.
“That’s your question?”
“No. Whenever you lie down on me like this your breasts smush and become a thick layer of ... you. It just looks like it would be painful.”
Molly made her upper torso go in a circle wide enough that her breasts changed shape constantly. It was obvious she was doing it intentionally. When she came to a stop she kissed his chin.
‘“No. It doesn’t hurt. I love pressing my breasts against you.”
“That is my question. Why is it that when I was tutoring Robin, before anything sexual had happened, why is it that you wanted to have sex with me?”
“I didn’t,” she said.
“You didn’t what?”
“I didn’t want to have sex with you.”
“Um ... here we are,” he said.
“I know that, but I can’t explain how I felt back then.”
“I knew you were conflicted,” said Marcus. “You would look like you wanted something but then you’d clamp that off and talk about something else.”
“I didn’t believe that what I wanted was possible, or proper, or even legal. I kept trying to tell myself that I couldn’t have you that way and shouldn’t have you that way. I should have fired you and told you not to come back.”
“I’m glad you didn’t,” he said.
“I’m glad I didn’t, too,” she said. “It was like a fairy tale. There was magic involved and it was suddenly fine and dandy to put you in my fantasies as I masturbated. I knew I shouldn’t try to seduce you.”
“I was trying to seduce you,” he said.
“You said the most beautiful things, and acted like the man I had always wished I could meet. I should have realized your black magic was involved when I told you to seduce Robin!”
“But you can’t remember how it started in your mind?”
“I remember you being honest about how you felt about me. You were salacious but in a polite way, somehow. You said you wanted what any man would want, but you didn’t try to make anything happen. I felt like you were very dangerous, but at the same time I knew I was safe with you. I got horny and I knew you were horny but still felt safe with you. I remember that.”
“Okay, so I wormed my way into your panties by being a nice guy. How did that lead to you, doing what you’re doing, knowing it could make you pregnant with a black baby?”
“Remember when we skinny dipped and masturbated together in the pool?”
“Ohhh, yeah. I’ve wanted to do that again many times.”
“It was crazy. I wanted you to take the place of my husband, who didn’t love me. You respected me. You made me feel good. I think you made me feel loved. I know you’ve done that dozens of times since then. Anyway, I felt like I was cheating on Brad, except it wasn’t cheating because we weren’t even touching each other. And when your semen floated up in those lovely little curls and blobs, I had this insane thought that it belonged in my body, instead of in the water. After that, I couldn’t put that out of my mind. I tried to by imagining being pregnant and delivering a brown baby who I knew I would be able to love and cherish as much as I love and cherish Robin. Like I said, there was black magic involved.”
“Why black?”
“Because you’re black and you magicked me into letting you make a baby in my womb. And when Robin is old enough you’ll do this to her and I’ll have a little mixed-race grandchild to love, too.”
“Do you know why I want to breed you?” he asked.
“Uh huh.”
“Tell me.”
“You know.”
“Tell me anyway.”
“You want to claim me, clear into my womb. You want all other men to see me and know that they wouldn’t have had a chance because I was already yours.”
“Nope,” he said. “The reason I want to breed you is because I fell in love with you. If you want to talk about magic, it had to be magic that made a young black man want a white woman old enough to be his mother. It was magic that made me want to overcome every taboo on the planet. Everybody else didn’t matter. It was as if there was nobody else in town. I felt things for you, a stranger and a white, that I had previously only felt for my mother and sisters. I knew what I felt for them was real love, and that meant I was in love with you.”
He reached to squeeze her ass cheeks.
“It was after that that I wanted to claim you clear to your womb so that every other man would know you were off limits and they were too late. Even though I knew it would be dangerous and stupid to walk around holding the hand of a pregnant white woman, I wanted to do it.”
“You want to own me,” she said.
“No, I want you to want no other man but me.”
“Well, that’s not fair,” she said. “You get to love and have sex with your mother and sisters and eventually Robin and all I get to have is you?”
“Yes,” he said. “But that’s different.”
“Why is it different?”
“The stallion chases all other males away to keep all those lovely mares for himself. It is just nature’s way. I am the stallion and I have five mares to protect and breed.”
“I want to be on the bottom,” she said. “I want you to give it to me rough.”
Instead of lying on top of her he put her on all fours. It was the first time they had used that position and she resisted until he slapped her once on her right butt cheek.
“Behave, woman!” he barked. He nosed the tip of his erection between her fat, slippery pussy lips and slammed deep, bouncing off of her firm cheeks. “I’m trying to breed my mare!”
She looked over her shoulder at him with a smoky look in her eyes.
“You’re too late. I’ve already been bred.”
She put her head on the sheet and clenched his cock with her muscles.
She was so excited that she came twice before he pushed deep and let loose.
As he spurted into her birth canal, he imagined her egg reenacting how it had been fertilized while he didn’t even know it was happening.
He almost laughed as he felt the same thing he had felt all those times before this.
He had always wished he was breeding his partner when he spurted in her.