i jerked off on my 19 yr old step daughter w her boyfriend

ive been with her mom for 7 years, last year she graduated high school and moved from her dads in w us. i was smoking weed and drinking with her and her bf when she whispered something to jim, he nodded, and asked me "do you want to cum on her w me?" of course my first reaction was "what?".. he clarified "she wants us both to jerk off and cum on her, is that cool?".. i thought about it and said "hellyeah".
we went into the living room and she took her shirt off, (she wasnt wearing a bra), slid her shorts down and immediately started rubbing herself.
him, and i pulled our dicks out watching her and pretty soon we were both rock hard stroking ourselves. after a few minutes she started to moan and he jizzed all over one of her tits.. i lasted a little longer before i jizzed on the other one. with both our cum dripping, she got off loudly. when we all caught our breath, we got ourselves together and smoked a joint