Darenimo Naisho de.
Uke is a popular guy in school. He doesn't want to have sex with someone he didn't love so until now, he was a virgin. Seme saw uke in the gym storage house, and heard the convo. Fromt here, seme knew he was a virgin and blackmailed the uke to go out wwith him.
Bitansan Renai
One guy fell in love with sensei then confesses, but is rejected by sensei. The event was caught by another guy and this guy, conforted and became the sex friend of his classmate. The love of sensei was the older brother of the one whi comforted the rejected guy.
Kimi no Oto ga Nari Yamanai