Your friend confronts you

"Damnit how could you have sex with your best friend's girlfriend?" Masumi angrily confronts you after learning you were paired with his girlfriend.

"It's not Keiichi-kun's fault!" Naomi defends you. "We were paired by the teachers. And you had sex with another girl too!"

Masumi flushes red. He was paired with another girl from Group B and had impregnation sex with her so it's not like he has the moral high ground.

You and Naomi have another mating session on Wednesday. This time its a lot less awkward and you kiss each other passionately while having sex.

You ask Naomi, "does it feel good?"

"Yes," your best friend's girlfriend moans, her tight wet pussy filled with your cock. "You are a lot better at sex than Masumi, Keiichi-kun!"

Naomi's words fill you with increased vigor. You fuck her more vigorously and creampie her four more times that session.

"I'm very pleased with the two of you, Naomi-san and Keiichi-kun," Yukiko-san, your teacher, gives you a glowing review. "You've performed extraordinarily. Keiichi-kun's penis fits inside Naomi-san's vagina perfectly! Your physical and sexual compatibility gets an A+!"

You and Naomi flush red. It's true your sexual compatibility is off the charts and every breeding session has been intensely pleasurable.

"Masumi doesn't need to know about it." You and Naomi meet again on the weekend to have sex without Masumi's knowledge. It's technically cheating but you justify it as homework. You have unprotected sex with your best friend's girlfriend on your bed and repeatedly cum inside her.

A few weeks pass and the pregnancy test finally comes positive. Your best friend's girlfriend is pregnant with your baby!