Wiktionary
man-on-man
a. 1 (context informal English) Involving sexual contact between men; homosexual 2 (context sports English) referring to a defensive play where each player man-marks his opposing number.
Usage examples of "man-on-man".
It was after Manus couldn't get guys to approach him for sex that he started into buying man-on-man sex magazines and going out to gay clubs.