Anyone who knows about earings, please help :-)

The other day, I bought an earing for the piercing at the top of my ear...but I can't quite figure how to open it. Which is a bit of a problem when I want to get it through the hole in my ear. It's circular and has a little metal ball on it, and looks like this, basically:

>>>>

I've tried pulling it apart and twisting the little ball, but they didn't work... so if anyone has any ideas...PLEASE HELP :-) thankies!

Ugh, I have another problem as well...My mum and my brother went out yesterday to buy a birthday present for my sister's eighteenth from me and my brother. I couldn't go with them because I was doing stuff, anyways...they got a necklace for her, but I really don't think it's really her style...at all. It's quite big and chunky, but she prefers small dainty pretty stuff. I told my mum, but she wouldn't listen to me, and now she's being all grumpy with me...pfffft.
Plus, the damn thing looks like it cost about 10 pounds, but it actually cost 200....ugh. I love my sister to bits, and I really want to get her something she likes!!!! I don't want her to have to pretend she likes it, and force herself to wear it......I know this sounds like a pretty ridiculous thing to get upset about, and a lot of people have much bigger problems...but anyways. I'll stop whining now...

bye bye :-)
xxx