A party where you dance madly in mounds of foam. Otherwise known as a wet orgy.

someone who is sexy beyond mean

When a girl masturbates so ferociously her pussy juice is whipped up into a foamy lather. The term can be applied to a solo wank session or a group of masturbating girls that have gathered for the occasion.

To gather a group into a bathroom and brush your teeth.

A foam party is a collection of mates all vomiting on the same spot, with the aim of creating the biggest foam bubble possible.

This is best accomplished by consuming LARGE quantities of beer, as beer seems to give a consistently larger volume of foam per regurgitation.
To increase the foaminess, it is reccommended that you do anything active just before you're about to start the foam party... some examples include: hedge diving, cart-wheels, or jumping-jacks.