Custom Shoe Size
The insertion of a male's foot into a female's vagina while the girl is extremely trashed, whereas the man will then walk around using the female as a shoe
"Man, these shoes never seem to fit!!! I think I will take Mary's offer of giving her a custom shoe size."
"I had sex with you mom last night!!!"
"Oh yeah?!! well i gave that bitch a custom shoe size!"
"I had sex with you mom last night!!!"
"Oh yeah?!! well i gave that bitch a custom shoe size!"