To be highly inebriated, smashed
, etc. It is a combination of the words "shit" and "housed". I'm sure you're aware of the term "Shit Faced", well " Shit Housed" is a very similar term. Shit-housed, or "Shoust" is a term used when someone is very intoxicated.
Variations on the word are highly encouraged. IE, shousted, shoustify, shousting, shoust fest, shoustness, etc.