Sex friend. It's short for sex friend. Not a lover or a wife, but a relationship where you enjoy sex. I have a girlfriend, but I was feeling like things were getting a bit stale, so I found my first sex friend through an app. Gagging, blindfolding, cumming inside... I really want to do those things, but I couldn't because I was afraid she would hate me if I told her. But with this sex friend, anything is OK. There's no need to worry about reason or appearances. We did it over and over again just to satisfy our sexual desires and preferences.