a fat mom, usually living somewhere in new england. Generally this rare species of fat asses are found in the southern most parts of maine. When Hip-Hip is shouted, it is only appropriate to yell OHHHHH in response. Usually this is not understood by aging women.
Mom: "Do I look fat in this shirt?"
Girl 1: "Hip-Hip..."
Girl 2: "OHHHHH!!!"
Mom: "WHAT?!?! I don't get it."
Mom, you're a Hip-Hip...Oh.