The Mashed Potato 

A sexual maneuver whereby a male inserts or "mashes" his soft penis into a woman's vagina. The penis then becomes erect, leading to the term "baked potato." This term comes from the song "Do You Love Me?" by The Contours. In the song, they sing "I can mash potato." Originally an arcane dance form, this term has taken on new meanings in the bedroom. This term was coined in a Minneapolis basement by three men playing ping pong.

Steve: You give her the mashed potato?

Mike: Nah, man. I was already hard.

Steve: Yeah, it's a difficult move. The only way to really do it is if it's the seventh time for sex that day.

Mike: Or you could not be into vaginas.

Steve: True

The Mashed Potato by Stu Pendos January 10, 2012

The Mashed Potato 

A technique used in male masturbation. Instead of stroking the shaft up and down, the motion is circular. Resembling the mashing of potatoes.

Steve: Hey man, what did you end up doing last night?

Tom: I got bored and tried The Mashed Potato.

Steve: What!? What was it like?

Tom: It was..... incredible.

The Mashed Potato by Father of God June 30, 2010

the mashed potato 

When you're unaware of your pregnancy and you still have sex.

"What the hell? I don't what happened to Jimmy, but he be looking like he got the mashed potato. Not sure what happened to him, but when he came out, he came out in pieces."

the mashed potato by TheSpizzleWizard December 6, 2021

fuck the mashed potatoes 

Slang for the act of ruining a meal for the other diners. Generally used in the context of a dinner party at a private residence, but can also apply to a meal enjoyed in a restaurant.
A more general definition applies when someone manages to spoil an event for the group by doing something very inappropriate.

Every time my girl and I double-date with James and Amy, We end up leaving early because James always manages to fuck the mashed potatoes by drinking too much and starting a screaming match with Amy about who spends to much money.

fuck the mashed potatoes by MikeinVA January 2, 2008