An onomatopoeic word indicating sharper, intermittent twitches; often stronger or more pronounced than ピクピク.
注射をするとき、子どもの腕がぴくんぴくんと動いた。
When given the injection, the child's arm twitched sharply.
電気が走ったように足がぴくんぴくんした。
My leg jerked sharply as if an electric shock had passed through it.