I've been on the receiving end of this before.

One of my roommates in the past had a but of an exhibitionist girlfriend who would regularly walk past me in nothing but a small towel and frquently asked if I ever jerked off listening to them having sex. She also dressed up as a dominatrix one halloween and let me slap her ass with a riding crop all night.

Another roommate of mine had a gf that was very flirty with me. She wouldn't let me see her naked but dressed up to tease me and would often initiate hugs where she would wrap her legs around me and our lips were perilously close. She also taught me exactly how she liked her neck kissed to get her wet, which "Technically" isn't cheating but I'm sure her BF wouldn't have been happy.