the act of fucking a female in the vagina or anus, and at the same time an open beer bottle(with beer still in it)is inserted into the hole that the male participating in the sexual act isn't fucking.
Bill: dude! you two got so messed up last night. What did you guys do when you went back to her place?
Frank: I Designated Drivered her ass! she was so drunk and horny she didn't care. so i opened a new bottle and went miller time up her ass.
Bill: KINKY! i wonder if patty will let me Designated Driver her?
Frank: your sister let me Designated Driver her.