Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: Basically I have a little sister who turned 15 two months ago, whose beEn getting texts from a guy in my highschool whose 17 about to be 18 in a few months.

I have seen how this guy talks about sex and girls and I get weird vibes from him. Ive told my sister this but she keeps telling me to butt out but I know this guy is sort of like a wannabe gangster type (but also like a wannabe intellectual as well, very weird combo but its true).

So i told him directly to stop messaging my sister, hes too old and too freaky for me. After trying and failing to buck me down (getting in my face and asking me to repeat myself) he then tries to say im "sexually gatekeeping" my sister and that hes gonna tell other people that im weird/possibly incestuous.

Honestly it got loud but no violence and we got separated by the AP. Both got an ISS for making threats. My sister is angry at me. AITA?

telling a guy from my school to stop texting my 15 year old little sister