Something that cannot be urinated.

Specifically, it's a nonsense word from the famous iCarly YouTube Poop "Freddy Runs Sam's Life", for a sentence-mixed version of a joke by Spencer. It makes as much sense in context, but the line became quite famous for its absurdity.
"Anyone can suck penis, but nobody can pee sucknis."
by Camwood December 15, 2020
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