All I remember was it was between these two guys and it was at a subway station, and basically they'd make eye contact as a signal to head to the bathroom and fuck :D
https://www.mangago.me/read-manga/namae_mo_shiranai_machiawase/
All I remember was it was between these two guys and it was at a subway station, and basically they'd make eye contact as a signal to head to the bathroom and fuck :D