Oh what a lucky problem I have, I know I know. 
I have two kittens - a brother and sister at 5 months old.
The male is very charming indeed. He doesn't sit on my lap or get too close, but he does rub against my legs when he wants something and will occasionally purr when i'm near by. In the mornings he'll want a little head scratch when i wake up.
His sister on the other paw is his polar opposite. Every time i sit down, she'll jump on my lap. She'll start kneading me and sucking on my sleeve. She purrs constantly when I'm around. Right now she's putting her nose under my hand to lift it from the keyboard as she wants me to stroke her head. For the millionth time this evening. She follows me everywhere too.
Is there a way to get her to be a bit more like her brother? Don't get me wrong, i love how cuddly and affectionate she is - and often wish her brother displayed a bit more of these traits - but it's all the time.
As soon as i come home from work or the shops - she's there following me. As soon as i sit down, she's there kneading, sucking, licking me. Even her purr is starting to grate on me because it's constant. It's nice to know I'm loved, but it would be a bit like dd telling me every minute of the day 'IloveyouIloveyouIloveyouIloveyou'. It sort of loses its meaning after a while, and now i just don't believe her.
Any tips?