3rd Rock from the Sun - Season 5 Episode 11 -

When he learns that Mary is seeing a therapist, Dick's paranoid about what she might be saying about him. Meanwhile, Tommy's intimidated about having sex with Alissa when he finds that it won't be her first experience. When Mary's rebellious niece Tiffany comes on to him, he is only to happy to dispose of his virginity -- and to inform Alissa he has solved ""their"" problem. (Can this be the end of Alissa?)