i just had this happen to me today, it happens to me a lot. I think, depending on who's asking, either it's flirting or they think you like them so they're leading you on. This is just based off of observation. a lot of people think I like them because of my flirtatious demeanor, but that's just my personality. I'm also conventionally attractive so a lot of the time flirting happens and I think they're just being weird. I'm not formally diagnosed but my mom is qualified to give diagnoses and she said I have autism soo? sorry for yapping lol. another reason might be because you're taking big bites or you're eating weird? this is my conclusion because I'm self-conscious, so idk if it's correct. i just really wanted to know why this happens