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1.
An often awkward sexual situation where in a crucial instant, you realize a person's gender is not what you originally thought it was.

Symptoms include sudden nausea and throwing up, guilt, invasion of suicidal tendencies OR complete indifference.
One tumiki situation:

<Vermillion> omg sabrina was a guy the whole time
* Vermillion throws up
<Inari> ROFL VERM DIDN'T KNOW


Another tumiki situation:

Karsh only swings both ways if he's getting it on with a hot girl and then it turns out he's in a tumiki and she's got a penis.
by Master Debater November 19, 2004