In search of a certain yaoi

Hey guys!
I'm searching for a yaoi manga, where the uke has such a wild imagination, that he feels it for real.
So in that one scene he's sitting in his classroom and imagines having sex with that one girl in class and gets an orgasm. But while doing so another classmate the seme finds out and uses it to his advantage by saying pervy things that the uke imagines and gets him hot.

I really wanna reread that, bu tI didn't put it in my read list.