I've had co-workers that I knew were into "extra" fun.
Most were women. I'd overhear conversations, woman talking to another about them(a married couple) having (fill in the blank...guy) over for bbq...
I never really put it together till years later.
Way befor wife and I were into this we knew 2 different couples that were into the "lifestyle". I never knew to what extent.
Now...since wife and I are into this but we keep it VERY private, I can pick up on how others speak about a "party" or have a "guest" for the night.
If anyone we know is into sexy play I don't want to know. It would only mess with my mind.
Befor wife and I were into this we were kinda close with an older couple from church. He was an elder at the church, older, frumpy, not attractive at all. His wife was nice, polite, ok looking for late 50s. We'd been to each other's homes for dinner, cards, etc. One night they invited us over for dinner, we arrived, they had a guest staying the weekend, no biggie. We enjoyed dinner, some conversation with them and their guest. Guest was about 40 (we were in our 40s), polite, very attractive. All good.
A couple of years later the hubby gets busted-caught fucking a fuckin ugly, fat church wife IN THE CHURCH during the week. Turns out the couple was into inviting females into their sex fun. That's fine but the women were ugly as hell, fat, typical no self esteem types, most were looser single moms that attended church. You just never know...