When a girl has really large breasts, or wears H-cups.

When a gay guy wants to torment his straight friends by shaking his H-cups in their face. These H-cups are usually pillows.
GAY: Look, my straight friend is sleeping. I'll shake my hippo cups in his face.
STRAIGHT FRIEND: Dude get your hippo cups out of my face!
by c. richy May 9, 2007
Get the Hippo Cups mug.