Two white chicks 69'ing while one black guy fucks one in the ass. Hence open-faced.
(2 white girls in a car with one black guy)
Hey, dinner was great! I just realized, despite the fact that Arnold's not here and we can't have a traditional double-stuffed oreo, we still have all the ingredients for an open-faced oreo!. Oreo (double-stuffed, open-faced).