I don't if it is a manga or a one shot, but I'll give it a try to tell about some things that happened in it.There's 3 childhood friends (let's call them X, Y and Z for now). X and Z fight a lot (I meant like punching each other). They like Y but they didn't confess. They have sex with each other thinking of Y. (lol I'm embarrassed rn). X and Z were meeting more often without Y and he was jealous about it, so one day at their school he searched for X and Z to talk about this issue, and saw them having sex in a club room. I don't if he entered the room right away or if he spied on them other days until they found out. Maybe Y heard they calling he's name, that' another possibility. Anyway, Y got a tennis racquet and hit them with it (I was confused at this moment). But they are basically EXTREMELY MASOCHISTS and then they started having a threesome. (Y was mainly seme, but he was an uke one time too, I think)I hope I didn't get some part wrong ;-;sorry for my really strange taste in yaoi^reallytyvm ~(also, sorry for my bad English) 6r4bn

Chapter 5 of Sachimo.