This role-play is performed by adults. A wife returns home to give birth. I was living alone for the first time in a while and was having sex all the time. My wife's sister came to my house, knowing or not. ``Brother-in-law... aren't you trying to cheat on me?'' I couldn't hide my agitation when my sister suddenly got to the point... ``I'll take care of it for you so your brother-in-law doesn't cheat on me...''...