In this universe, a cocksmith is a maker of stopcocks.
At one point, Thaddeus calls himself a "cocksmith." At first this seems like a random dirty joke that just doesn't make any sense. But maybe he's referring to stopcocks. Maybe Thaddeus is actually saying that he's an expert at crafting metal stopcocks for his kingdom's piping system. It sounds dirty to a modern audience, but maybe it would make sense in a medieval context, by analogy with the terms locksmith, blacksmith, goldsmith, and so on.
It could also be a reference to him drinking so much, a stopcock is used on wine barrels. He is a master of opening and then drinking barrels of wine.
The witch who put the chastity belt on Isabel was her mother.
Isabel talks a lot about avenging her murdered father and brothers, but never mentions her mother. Putting a cursed chastity belt on one's daughter is exactly the kind of thing an over-possessive, evil, demonic mother would do. Clearly, Thaddeus and Fabious weren't the only ones who had family problems to work out.
The entire adventure is a role-playing game, unfolding as the nerds get progressively more stoned.
A small group of twenty-something-year-olds just finished a very difficult semester of college, and are celebrating in a living room with a D&D-like game, and lots of pot. They aren't taking this game too seriously, and are letting themselves go absolutely crazy with the cursing, filthy jokes, political incorrectness, and drug references. The Dungeon Master is playing the parts of Leezar, the dwarfs, Martiti, and the other villains and minor characters. The guy who owns the house is playing Fabious; this guy is a dedicated role-player, and has chosen to play his character mostly strait, but lets the others go crazy with the humor. His recently-wed wife is playing a video game on her own, but is partially involved with the role playing game, as the part of Beladonna. The guy who provided the pot is playing Thaddeus, and he's the one who really got everyone going with the story's crazy direction. His girlfriend is a new member of the role playing team, and the only other girl, and decided to shock her new guy friends by making her lady warrior as over-the-top blood-thirsty as possible. And a third guy, finally, is playing Courtney.