Snowballing

verb

1. To rapidly grow out of proportion or control.

   "The high unemployment rates quickly snowballed into a major budget problem for the government."

2. To play at throwing snowballs.
3. To pelt with snowballs; to throw snowballs at.
4. (sexual slang) To receive a man's ejaculate in one's mouth, and then to pass it back and forth between one's mouth and his.