Hi!
I read the manga a long time ago. It was about two boys apparently and one of them sectrely fell in love with the other. But the boy (who fell in love) had been straight all his life and he didn't want to accept the fact he was turned on by a guy. Anyway, he couldn't cope with his obsession so he started to blackmail the poor gay boy and offered "converting-gay-into-straight" lessons so he could touch his secret crush because he had an exuse for that.

Does it bring any bell?

thank you anyway!

That sounds interesting. Do you remember if it is was just a oneshot or was it one volume long? I would like to read it too.

Two manga come to my mind Darling and Interval. Is it one of them?

Yes, THAT'S DARLING! OH THANK YOU VERY MUCH!