Definition of "squick"
squick
noun
countable and uncountable, plural squicks
(slang) A source of individual psychological discomfort; something that repels one.
Quotations
since it is pretty hard to find two people on such pics in the proper positions i ask those of you interested in the creation of this to keep yer eyes open for good source material. send me anything... suggestions, own ideas of how the squick should look like (het, gay, lesb (with plastic dildo or something)), reactions to this idea, material, whatever...
1993 June 19, Ulf Kastner, “how 'bout a squick.gif”, in alt.tasteless (Usenet)
verb
third-person singular simple present squicks, present participle squicking, simple past and past participle squicked
(slang, intransitive) To be grossed out, to experience disgust.
Quotations
He likes intense sensation (pain, for those of you not up on this lingo) and we did play with sounds. I'll now explain what "sounds" are, but if you squick easily, you should skip this next paragraph.
2005, Maxim Jakubowski, The Mammoth Book of Sex Diaries: Online Confessions and Call-Girl Adventures, page 27
(slang, transitive) To sexually penetrate a disgusting part of the head, such as an eye-socket
Quotations
Every now and then somebody on the alt.tasteless line mentions a certain perversion known as "squicking" which I assume is an urban legend. This act is similar to skull-fucking (intercourse with the socket of somebody's empty eyesocket, another act which I assume to be an UL), but instead of plucking out an eyeball, the perpetrator trephans the skull and thrusts between the hemispheres of the brain (incidentally killing the recipient).
1992 April 27, Douglass Glen Whitman, alt.folklore.urban (Usenet)