How do deal with ual Harment at school! HE IS A FREAK!?

I sit at a lunch table with my friends at school. There is a kid who was always funny until this year. Now he makes bad jokes about nasty things. He makes comments about wanting to do nasty stuff with the most popular girl, Riley. He says he wants to make out with all the girls in his grade and even kissed my Best friend on the arm. He likes everyone but me which I am happy. He is scared of me because every time he makes gross comments I kick him in the knee, not to hard but enough to tell him ti stop. He keeps calling me bad words trying to get attention. But he made disgusting hand gestures suggesting stuff that would happen in his dreams of him and Riley. She knows and she is disgusted about it. He also said he wanted to do nasty stuff to my best friend. He used to like me too but he started to hate me this year when I started getting mad and saying him to stop. He isn't like the normal guy who would just stop when you tell him to or nothing like that type of guy at all. He talks in a baby voice and the teachers don't know the difference. He flirts with every girl except and says suggestive themes with them and him. The only reason I am saying anything about it is he is bothering me and calling me bad words and calls other girls bad words. I hope someone will answer. Thank you in advance!