Selma Blair and Sarah Michelle Gellar
Movie: Cruel Intentions (1999)
Cruel Intentions was based on Les Liaisons Dangereuses, an 18th-century French novel with more juicy sexual intrigue than we care to explain here, but the setup for this special moment is pretty simple: Cecile (Blair) is a sexual newbie, while Kathryn (Gellar) has been around the block more than a few times. Cecile is so green she hasn't even French kissed a boy. Kathryn takes it upon herself to pop Cecile's mouth-cherry, and kisses her demurely on a park bench. Kathryn then tells Cecile what will happen next: "Okay, let's try it again only this time I'm gonna stick my tongue in your mouth, and when I do that I want you to massage my tongue with yours. And that's what first base is." The tongue-tastic action won the prize for "Best Kiss" at the MTV Movie Awards.