1. A term used to describe when a woman's IUD or other feminine hygiene product can double as a flotation device.
A police officer at a press conference today said and I quote: "We found the remains of an unidentified, half eaten woman washed up on the shore this morning at approximately 6:15 AM. It appears she used her maxi pad as a sort of pontoontang. Little did she know that she was also chumming the water for sharks in the process."
The act of swaffling (smacking your penis against something) fast and furiously between a woman's breasts. Similar to motorboating but with a penile element.
You could motorboat your girlfriend, but may derive more pleasure from pontooning her instead. Just make sure it is ok to ejaculate in her cleavage before doing so.
Jennifer: My girlfriend and I tried pontooning last night!
Debra: Oh my goodness you gotta boat?!
Jennifer: Noo no no, we both took Viagra and watched our shit swell up, it was like two huge fat pontoon boats!