Radio contest

Local Radio station had a contest to win a trip to the Big Apple. One of the morning qualifiers was a "motor-boating contest" in which you had to motorboat your partner. Now I was slightly puzzled by this challenge and a lot of guys were calling in and failing as they didn't have a partner.

Finally later that morning they had a winner, but because of what happened they decided to play it again the next morning. A girl called up with her girlfriend and proceeded to motorboat her. The guys on the station were drooling over this whole bit. I however was still puzzled, even after listening to the motorboat.

I broke down and asked my friends to please clarify the situation... and I'm still laughing about what it is!! For those of you who are puzzled:

Proper Motor boating etiquette dictates that a woman squeeze her chest together and upwards allowing ample room for another party to raspberry them vigorously.