adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
twitching; spasming
Describes small, repeated muscle twitches or spasms, often involuntary. Used adverbially with と or as a する verb.
まぶたがピクピクする。
My eyelid is twitching.
疲れると、足の筋肉が
When I'm tired, the muscles in my legs twitch and cramp.