Slurkey is simply a mix between a slug and turkey. It is quite a "meme" of an animal as the youths might say these days. It is imaginaryof course, but a great way to describe something that is a meme, a bit slimy, or funny. The reason these two particular animals are used to describe such things is because turkey are funny. Slugs are gross. It's just facts.
"Bro that shit is so slurkey!"
"Eurgh he's really slurkey.....ew"
"Nah don't say that man, it's really slurkey."
When an in-law lubes their hand up with the fatty grease from the turkey and gives you a hand job under the table while the rest of the family is totally unnoticing....