Why is hans instead of sitt wrong?
Still waiting for an explanation on this...
Given how the phrase is structured, it can't really be any other face than his own. And since it's his own face, Swedish uses a reflexive pronoun.
Does the ball have some other meaning relating to male anatomy, like in English?
No, but "kula" (marble) does
Nope, boll is not used euphemistically.
Au contraire, I've actually heard it used like that. I believe it's a clear anglicism. And I've only heard in on a few rare occasions.
Is "Kula (-or)" also "bullet(s)"?
How do you say "ouch" in Swedish?