I don't have CP but with Fibromyalgia sometimes I can't even pick up a glass. Then I have to drink from straws. Drawing with a pencil is very hard for me now so I use Poser as much as I can. But when I do draw or write with a pen or pencil, I adjust the way I hold it and rest often. Painkillers are something I can't take much of due to allergies. Try teaching yourself to either hand (yes, you can if you work at it)so you can switch back and forth. I write or draw with either hand, a trick I leaned in grade school due to sprained wrist at test time...lol.

Let me introduce you to my multiple personalities. :)
     BluEcho...Faery_Light...Faery_Souls.