I remember very little but one guy took the other home probably from street and I think the other one had a tattoo on his back so the first guy was worried that he took some yakuza's partner. The one from yakuza had long blond hair and I think he was actually an heir but I'm not sure?
I'm not sure whether it was whole manga about them or they were extra to sth
http://www.mangago.me/read-manga/yondaime_ooyamato_tatsuyuki/ is it this one?
The plot is happening when they work in the same office already and one recognizes the other cause he was served food by him in some cafe long time ago. I think one of the has a sweet tooth/likes food(his coworkers gave him some from time to time) and I'm not sure if this is the same manga but in one of last chapters the food liking one loses his sex drive due to eating too much sweet stuff?