Should I? sorry! This question is so long help?

He's young, horny (right in the middle of his sexual peak years), and being led by his penis. He is looking for someone to have sex with. He's hoping that someone could be you.

If that's not what you are looking for, you should tell him so. He'll probably lose interest and move on, but some guys will keep at it hoping that the girl will change her mind. If he does that, you might need to be more direct, such as blocking him on FB and so forth.

sounds like one night he got lonely, real lonely; and what he did triggered an insatiable hunger haha. He was honest be honest back. You don't like it, throw that in his face; don't mess him around by avoiding it or something, that'll make him more frustrated. that or turn him on but first tease him a bit but seriously once you made up your mind don't go back and say I don't want it.

Do you seriously think he wants to get to know you? What kind of person randomly sends another person a picture of their junk? Its obvious his testosterone are telling him to talk to you.

Keep him as your toy boy, that's what he is atm... If he liked you he would have the decency to wait till bed time...

Let him get in trouble for posting pics as such online, you don't need that happening to you especially after that whole Amanda Todd story. You can keep talking to him but if it becomes really bad, ask for help

He only wants to get into your pants. No romantic intentions.
Yes, you should stay away from him.

He wants to get laid. Is it really that unobvious?