my little cousins are getting out of hand

how do I tell my aunt that her kids need help...they're 8 and 6, boys, and I went to hug my 6yr cousin goodbye before leaving a family event and he humped me😰 these kids are raised off of tablets and i, 15 f, and my sister, 17 f, have told my aunt about their inappropriate behavior before but nothing changed. it started off as brain rot, then them moaning, then them saying daddy, and now they're humping the air and me😰 the boys are very reactive and get loud and mad easily and become uncontrollable and their mom tends to jst let them do what they want after yelling at them and their behavior not changing, and other adults ,like my mom and their dad has to get on to them. what do I do?