I used to do that too bro maybe buy the type of pens you can’t really chew? good luck, but there’s a lot worse habits, so don’t worry about it too much
put something on the end, tape a feather to it or something else that won't feel or taste good. If that doesn't work, pretend it's an Explorer... that should keep it away from your mouth or hand
If you ever want your dog to stop catching food you throw to it, throw a flaming hot Cheeto , that’s what I did now she will never catch another thing that I throw to her , ,, moral of the story dip all your pens in Tabasco sauce
Back in the day when kids got chapped lips the parents would rub chicken dodo on them, it didn't cure it but it kept them from licking them. Just saying.
They make clear nail polish with a terrible bitter flavor in it to help people who chew their nails. Some on the tasty part of the pen would probably help. I do something similar to help me not chew my fingers. https://www.amazon.com/dp/B00336WT3O/?tag=squiertalk-20
Commission a custom pen that you wouldn't want to chew or would deeply regret chewing. I made this one from a French oak wine barrel stave for my father in law.
I used to drink heavy, eat plenty, and chain smoke. One night, as a bartender emptied our ashtray, I told my girlfriend that I probably have an oral fixation. Her reply: (flatly) “Ya think?”