I take it they fart these toxic pheromones and that they are nothing like actual skunk spray (as in can go through clothing without ruining it if it is a gas instead of a liquid).

They can fart or burp the pheramone. The pheramone can also be harvested through their sweat. Prolonged exposure to their natural smell can increase resistances. Prolonged exposure to their farts can cause death or brain damage. The brain damage is not immediate, it something that happens over an extended period of time. Think of it as being on a serious drug. Good news is its not irreparable. Well the brain damage that is.

Furthermore if you overcome the brain damage, you can build up resistances to their pheramone.

So that's how it works. Interesting to know.