My cousin tried touching me.....INAPROPRIATLY?

im shaking he is like hey wanna go oin the basement and im like maybe later and my moms like yea go its got lots of games itl be fun. R U SeRIOUS y would she do that he is like a rapist. i am really nice to him so he dont get piss and rape me outa anger but he started touching me all over my back and my bra strap under my shirt and my waist and tummy and when ppl were calling him to leave he was like im not leavin till i get a hug and a kkiss. i was like no no no silly boy and he wouldnt let me through the door and he like held onto me and wouldnt let go and picked me up and threw me onto the bed but i ran back upstairs sumhow and got around where everyone was did he try to rape me and idk what to do now