friends with sexual tension
Being "friends" with someone, but both of you share a small amount of attraciton to the other. Could be because you are ex-lovers, or one is in a relationship, or that no one made a move when you first met, and now you're just "being friends"
I hang out with my ex-boyfriend, we're awesome friends... but it's more like friends with sexual tension, becase I know he likes me even though I have a thing for girls