From the popularLinkin Park song. You use this when somebody is being an angsty bitch and generally whining about their lives and how they have it so much worse than you. See angst
"Ricky's whining about how his girlfriend left him. CRAWWWLING IN MY SKIIIIIN"
Although the previous definitions may be right. The true meaning of the words comes from the feeling you get when your high on heroine and you feel as though you actually crawling in your on skin and your skin is moving and trying to come apart.
The ability girls and women have developed to hold several items at once in one hand. The skill has been developed due to the lack of pockets in women's clothing.
I thought she'd need multiple trips to carry her phone, keys, wallet, and Starbucks to her car since she needed the other hand to open the door, but she used her impressive girl grip to carry everything in one hand.