I have seen the terms "waste/gent of piss" fly about a few times, are they just very popular crack classpects or do they appear in canon somewhere?

Gent is canon.  Hussie’s said on his formspring that Fedorafreak had ascended and was the Gent of Piss. 

Waste is fanon. It came about because Hussie wore a space shirt in canon and people assigned that class to him.