curl up

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive, of hair to curl, make curly, shape into curls
• verb intransitive to become curly
• verb transitive to coil or shrivel, make into a coil
• verb intransitive to become coiled or shriveled
• verb intransitive to shape one's body into a somewhat ball-like shape, with one's legs tucked into the abdomen, especially for cosiness or for protection.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb shape one's body into a curl