When you pull your dick out of your girlfriend's pussy and then slam it back into her with such force that it causes her to cramp up, throw up, and then pass out.
A generic dance done mostly at a night club or bars when you can't relate to the music playing, or feel awkward doing so. Mostly done to upbeat music, the "murphboat" involves the arms and hands raised above the head pushing out in a swimming-type motion as you bounce to the beat of the song with the rest of your body.
Ducky: "Mike, what kind of dance is that??"
Mike: "It's the murphboat! Do the murphboat!"