I've had this fantasy of watching a previous girlfriend and her mother playing with each other.
The real part-
The mother caught us having sex once. I was naked in front of her as she opened the bedroom door. She saw everything.
The three of us had a long chat in the mother's bedroom afterwards. During the course of our discussion, the mom made some remarks with some sexual overtones. And comments about seeing my body with no clothes.
That's where my fantasy begins.
My girlfriend's mom is scolding us for having sex. She instructs my girlfriend and I to stand in front of her. Still naked.
She wonders how long this has been going on and such. When my girlfriend gets a little disrespectful with her mom, her mother tells her to get over her knee.
Reluctantly, she complies.
Her mother gives her a few seats on the butt, right in front of me. Then rests her hand on her daughter's butt.
She asks her more questions about our sexual experiences.
Then, as I stand naked in front of her, she begins fingering her daughter as she lay prone over her lap.
My girlfriend struggles initialy. Embarrassed that her mother is pleasuring her in front of me.
My penis becomes hard immediately. Mom sees it and comments on it. "Oh, you like watching me finger your girlfriend, don't you"?
She has me come closer. She leans forward and puts her mouth on my erection as she continues to finger my girlfriend.
... You can imagine how the rest of it goes.