a junior squirrel is typically being a little shit, annoying, or also could mean stop farting in public. These people tend to be boys, short ones.
Example 1.)
*student farts in class*
*teacher* “you are being such a junior squirrel”
Example 2.)
*barbra* omygosh did you hear what Betty did?
*linda* “no, what did she do?”
*barbara* “she ate my brownies, and I said hey those are for my grandson you junior squirrel.”