I don't get this joke, help?

Question

ok, this guy here on yahoo answers wrote a joke that people that was funny and I couldn't get it. Someone explain? 10 points

"a 20 year old virgin went to an old ladie's house to deliver a package. the man said sign here. she signed and then the man got back into his truck and left.

MUAHAHAHAHAHAHAHHAHAHAHAHA!!!!"

- exact words

Answer 1

wtf? y do we need to know that he's a virgin.  i think its dumb, and either its not funny, or i dont get it to :P

Answer 2

It has something to do with his p***s

but that joke doesn't really make much sense

Answer 3

I think he had s*x with her, hence the "deliver the package" thing, but I really don't know. I have no clue about the sign here thing, was he like a prostitute or something?? I'm with you, I don't really get it.