enjoying your story!

shtupid --> stupid

communitylawfirm.com/prison-slang-guide#A

This is helpful for prison scenes. Some of thses phrases would add more realism.  It's required reading for law-enforcement. I worked as a counselor at Leavenworth Prison in Kansas.  

Reminder, do not punctuate like this   "    !".   the final period is not needed in English.  You should do this when there is a quote inside a quote:
 thepunctuationguide.com/quotation-marks.html

I am not up to speed on British English, if you want that. I know their punctuation is a little different considering quotes.