When someone jams multiple penises into their mouth at once. Resembling the Lovecraftian God Cthulhu, but in reverse since the tentacles (penises) are going into the mouth instead of out.
At the gangbang, TJ reverse Cthulhu-ed 15 guys!
A sex position so odd that it looks like the participants are trying to summon an ungodly monster of some sort.
Alternatively: a kink for experiencing the deep, incomprehensible horror of humanity's inconsequential and powerless position in our universe. Like a knife play kink, but with way more existential dread.
"Man, I knew she was kinky, but I would never have guessed she would want to try reverse quadruple Cthulhu position."
"I told you she was pretty intense before you started dating."
"I know, but I figured you just meant BDSM or something."