This fits us too. Our friend isn't her bull he's a guy we invite in to have sexy fun. Nothing cuckold happens, we take turns with her, we all have a good time. Seeing her get really turned on drives me wild. They look so sexy together. We always do her twice each then they do one more before he leaves. She's horny as hell for days after so we have a lot of good sex.
She - we had a LOT of guilt when we first started doing this, we still do but we're all adults and it's fun.