fun way to say nasty, also implying that you really think something is gross instead of nasty as in cool. falls into the fun words category with schwasted and schwafted. if it's not fun to say, don't say it.
A: i just saw The Hills Have Eyes last night. some of those mutant people were really schnasty.
The point of intoxication that can only be described by a mangled form of the word wasted concatenated with an article of clothing to further emphasize the original meaning.
Steph decided that Jimmy was shwastypants when he began vomiting profusely in a friend's car on the drive home from the bar.