Mutual Masturbation Experiment Doctor Barber, an unorthodox therapist, records Eliasâ and Penelopeâs session, two stepsiblings who grew apart due to an incident they can hardly talk about. It seems that they were very close when growing up, but one day, Penelope caught Elias jerking off and their relationship got cold ever since. Doctor Barber suggests trying a mutual masturbation experiment to release the tension between them. As Elias rubs his stepsisterâs nipples and Penelope feels her stepbrotherâs cock, the two forget about their distance and become close again. To ensure this, the therapist joins in and spices things up with a lustful threesome that repairs the damage between the stepsiblings