pins and needles

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun plural A tingling sensation felt in a part of the body numbed from lack of circulation.
• idiom (on pins and needles) In a state of tense anticipation.

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

• noun informal A tingling or prickling sensation, felt in a limb when a lack of circulation is relieved and in other situations.

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

• noun a sharp tingling sensation from lack of circulation