Looking for a title

I just read this oneshot in which there were three childhood friends, two of them are always fighting and there's this third one that's apparently the one that puts order in the place. But in reality, the two that always fight usually make out with each other, and they're M, the third one actually had a hard childhood, always seeing his mother getting beaten and in truth, beating others gets him excited.

Does anyone knows which one is this? Thanks in advance!!