Re: need some help here pleeeeeeeese!
Yup, it's not okay to do this, you're right to feel uncomfortable. You didn't mention ages, though. I'm assuming he's younger than you.
I think it's his curiosity that causing him to do this, you might want to first set a limit with him, tell him it's not ok to touch your penis, and then ask him what's on his mind, what he's curious about, and that you'd be happy to address his questions with words, and you'd like him to ask his questions without using his hands.