Dose he like me or is he just being friendly?

Ok there’s this guy I started liking and he is only in my science class. Well we just started to talking to each other this year and it’s only been a few weeks since school has started, but for the past few days he’s been extra nice to me even to where I think he is flirting with me. He’s always trying to make me smile and laugh and today actually we were passing notes and this guy we both know saw us and he says hey no passing notes and I saw him say“ go man” to the guy I like and he was smiling and laughing so if he likes me how can I flirt with him back to let him know I like him back. Or is he just being friendly?

(P.s and he kept touching me today to saying my skin was soft and I smelled good)

but still I didn’t look up I just kept doing my work. So how can I make it clear that I like him by touching him physically?