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1.
Slashfic where a character is paired romantically or sexually with himself.

The most ridiculous, least socially accepted, and therefore the
hottest kind of pairing (im)possible.

"Do you ship Sam/Dean from Supernatural?"

"Nah, Wincest just isn't wrong enough. I ship Sylar/Gabriel Grey."

"Oh, selfcest, huh? Hot!"
by theflying_clubcup February 26, 2009
 
2.
The sexual attraction to ones self
She was caught engaging in selfcest activities
by jeack September 19, 2008