Usually takes place after a heavy night of drinking. This is where the female will stop at nothing and is desperate to have sex. Completely neglecting the fact that you may have whiskey dick, she vigorous "mashes" her vagina into your penis in hopes of stimulating a flaccid erection
Def1: when a girl decides to mash your potatoes, then add the butter and milk to make it taste good.
Def2: when ur mummy says dinner time and you run upstairs to smell potatoe in the air
Girlllll stap mashin my potatoes or ill skittle biscuit you! MaShInG PoTaToEs
Mom did you make mashed potatoes?
When during a blowjob the female/male giving the blowjob grabs a hold around the ball sac and crushes the balls.
Often done by people with "cbt" fetishes (check wiki) and also dominatrices.
"You cant believe how great it felt when Linda and I tried somethingnew, she really likes Mashing the potatoes. It really spiced up our marriage and felt great."