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.
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 emphasizethe 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.