While his class focuses on the fundamental parameters of music, Jonas is just as likely to tell his students about "that one time I got conked in the head with an empty Coors bottle at an Eddie Money concert" as he is to give a lecture on the harmoinc structure of freeform jazz. He's one of those teachers that's everyone's best friend, preferring his students call him by his first name and having a lax attitude towards class structure. Students are welcome to eat or drink in his class, and he can't exactly expect them not to curse when many of his favorite exclamations are of the colorful variety. Want to take a nap or skip class altogether? Fine by Jonas; just don't expect him to have much sympathy when you fail your midterm.
There's rumors that Jonas used to be a fill-in stage musician for this band or that one during his twenties, but he's not confirming or denying any such thing. But anyone who's heard him play guitar can make an educated guess on the validity of said rumors. While he doesn't teach a class on any particular instrument for the school, he is skilled enough to give lessons on a variety of them to any student who may be interested. One has only to ask if one is so inclined.