Please help me find this Manga

Can anyone tell me what the title of the manga? the guy (MC) has an unrequited love to ML who has a gf that died later MC confessed to ML and ended up did the thing then the ML committed suicide in the end?

I AM SO SORRY for the long pervy description. I wrote everything i can remember about this manga. But i really miss this manga & want to read it again!! (︶︿︶)