This is not a very difficult situation. Just curious what you'd do in this situation.
FYI:
her bio says "Don't even know what I'm doing here😅"
I'm not actually a teacher, sometimes I joke about being a teacher for naughty girls. In this case the girl seems to play along and playfully resist at the same time.
A few responses I thought of:
"Calling me sir already huh?"
"Are you a cute, feminine, submissive, adventurous brunette with a possible nice booty who enjoys a dominant man who can take control?" Then if she says "yes" I'd respond "Then that will do" and move to the close.
