SILF or SILFing. Self Inflicted Laughing Fit.

A SILF occurs when you do or think about something that amuses you so much you have a laughing fit. You might send a text to a friend that makes you collapse on the floor with laughter.
"I just handed out brochures whilst doing the chicken or beef dance to the theme tune of Air Crash Investigators. hahaha tears! I just SILFed myself!"
by VIK&GABS February 26, 2014
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Sister id like to fuck. Your best friends sister that you just wanna fuck like a horny dog until she cant take any more
dude, your sisters such a silf. I rode her all last nite
by silfassfucker January 10, 2009
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