Similar to the act of motorboating, but with a smaller pair of boobs. The face and mouth must go a farther distance between breasts, and therefore the motion becomes slower and more drawn out, like paddling a kayak.
Dude 1: I went out with a girl last night who had double Ds. I was motorboating those titties all night long.
Dude 2: Well, my girl is an A cup, but I still enjoy kayaking hers.