ahh, Bostons .. lovely lil dogs, but WOW they can have big attitudes!
I would say yes, the stinky stuff was anal glands, which they will express when scared. They might also pee when scared, I've never had a boston do it, but yorkies
As for him snarling and getting a bit barky, you need to scoialize him well with humans and with people. Check out the training thread on here for advice, there is one trainer, Tenderfoot that has amazing advice. Bostons are determined, and can end up very yappy, snippy dogs if not socialized well.
How did you acquire Tuxy? Breeder, rescue or shelter?