Gakuean heaven
 

wat chapter did the whole all boys thing happened cause im lost on this one site.

on Gakuen heaven

I do believe Gakuen Heaven was only a one-volume manga, it surely can't be too hard to find the chapter you want? They could only be about four/five chapters, surely? Sorry I can't be more helpful, but I can't remember an 'all boys thing' in the manga or anime, and I haven't played the game (in case that's what you're refering to). Hope you find what you wanted though :)