Mark and Alex are hanging out at home one cold winter day. Alex asks his friend "It's fuckin' freezin' in here. Can you go upstairs and get me my fuckin' slippers?"
So Alex goes upstairs to get the slippers and he comes across Mark's hot 21-year-old twin sisters. He tells them, "Your brother just sent me up her to have sex with both of you."
One of the sisters replies, "Yeah. Prove it!"
So Alex yells downstairs, "Hey Mark! Both of them?!"
Mark yells back, "Of course! What's the point of fuckin' one?!"