Vibrating ones lips over a females, hopefully large, chest.
The Motorboat cannot be explained, only enjoyed.
by Nick Beno July 13, 2006
v. int. The act of pushing one's face in between two ample breasts, and rocking one's head side to side very rapidly while making a vigorous, lip-vibrating "brrr" sound.

n. The sound produced when doing a motorboat.
Wouldn't you love to see Meatloaf motorboat Barbara Bush?
by Bill ewall March 26, 2004
A person, generally female, who you would love perfrom motorboat on. She possesses cleavage that is astounding, and absolutely breathtaking to the human eye.
Damn, Kelli brought her boobs out for work today. She's looking quite motorboatable.
by Taquan April 28, 2008
1. able to be motorboated. 2. the appearance of a womans breasts of being highly worthy of the act of motorboating, which is to dive in and indulge in a womans breasts with furous glee all the while making noises similar to that of a motorboat. also see motorboat (v.) and motorboating(v.)
Salma Hayaks Tits are so fuckin motorboatable.......

or

those 4D tits are motorboatable as hell
by wterasta March 10, 2010
To submerge ones face in large breasts and moving your head back and forth, flapping your lips, in turn making a motorboat sound.
I just motorboated Marygrace, I almost suffocated in those funbags but it was superb.
by Urban Dictionary November 27, 2006
ta-tas that are able to be motorboated
Yo dude! Look at those ta-tas! They are so motorboatable!
by michellebigboobs December 7, 2010
( . )BPBPBPBPBP( . )
The sound of the motorboat between a nice rack! Motorboat
by biteme2 November 19, 2011