When a male pours a blue Slush Puppy into the vagina of a woman - usually creating a burning sensation. This is a tactic often used by aspiring teenagers trying something new.
Vickey: How was it last night Annie?
Annie: It was horrible! Donald slush rushed me round the back.
When someone sticks out their tongue and their male partner ejaculates all over it, then it rushes down their tongue like slush on a mountain.
I gave that girl a good slush rush last night.