sexual harrasment?

Ok so there is this guy that is a perv or whatever and I stayed after school one day and he was there so it was just me and him and I sorta felt uncomftorble and then he started putting his hand on my butt and grabing my hand and laying on me and pinching my thighs and all. I wanted to slap him or just get away but I thought it would make myself seem stupid for not liking that stuff. And a day later I stayed after school again and to come to my surprise he was there. but anyways there was 2 other people there and they left and so it was just me and him then he grabbed me and he was sitting on the pole and he was putting me in between his legs and I didnt let him but he kept pushing me there. then he stopped and was all can I have a hug I got to go then I gave him a hug and then he was smelling me and putting his hands in my butt pockets and I couldnt move that much cause I was against the wall and he didnt lift up my shirt like you think but he was all how many shirts are you wearing and he just looked and left. is there something wrong with me not liking his sexual behavior? I fell sorta bad for not letting him because im afraid he will tell his friends that im a shy one. but then again im glad. what should I do? and a lot of kids at school make fun of people that have there v-card still and ones who arent involved in sexual activities.

if this sounds confusing then im sorry but this has been bugging me.