adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
itching to do something; eager; impatient
Describes a restless, excited urge to act, often with the body feeling fidgety. Commonly used with する or ～ている to express a state of barely contained eagerness.
旅行の前日はうずうずして眠れなかった。
The night before the trip, I was so excited I couldn't sleep.
彼は試合に出たくてうずうずしている。
He's itching to play in the match.