v. int. The act of pushing one's face in between two ample breasts, and staying motionless/silent, like floating calmly on two nice soft billowy clouds. Opposite of motorboat.
Madison laid down on the bed to let Ethan motorboat her, but Ethan was so drunk that he passed out as soon as he put his face between her breasts. Now he's just motorfloating on Madison's boobies and she's stuck there until he wakes up. I hope he doesn't puke on her!