1) A phrase, originated by Kurt Vonnegut, that now refers to one's clumsiness in reference to dropping objects or tripping/falling down.

2)Having an erection at an inopportune time.
God: Man, I keep dropping stuff.
Shiva: Must be a high gravity day.

Lucy: Check out Tom trying to hide his high gravity day!
Sally: What a wanker.
by Holy Moses Roller Brigade March 13, 2008
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