While getting head from someone, they have ice in their mouth and putting fingers up your ass. The number of fingers determines the gallons of the frosty. For example, 1 gallon frosty being one finger, a fist being the five gallon frosty.
I know a chick with petite hands that works at Wendy's that I'd like to give me a 5 gallon frosty.
by Vajageddon March 06, 2010