Based purely on the conversation in isolation, yeah it could be taken as “what’s the craziest (not necessarily sexual) thing you’ve done?”. Imo though, generally if someone dms you under a more sex-related post, they’re trying to sext with you. Otherwise, why not just comment? Why do you feel like you have to ask op privately? Sometimes the covert sexting attempts are more obvious, but my general baseline rule for anyone dming me under any post that could potentially be construed in a-