Stepmom teaches her stepson how to have their first sex

I have a dinner date tonight so I wait at my boyfriend's house but I am greeted by his son while my boyfriend arrives at the house, my stepson is very nervous and I am very horny, I ask him if he has a girlfriend, he says no and that he has never had sex, I take advantage of my horniness and teach him how to have good sex, until my cell phone rings and my boyfriend almost discovers us.