adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
Describes a gentle, rhythmic, or unsteady side-to-side or up-and-down motion. Often used for flames, hanging objects, or a person's unsteady movement. Can be used adverbially with と or as a する-verb.
ろうそくの火がゆらゆらと揺れている。
The candle flame is flickering gently.
ブランコがゆらゆら揺れている。
The swing is swaying back and forth.
酔っ払ってゆらゆらしながら歩いている。
He is walking unsteadily, swaying because he is drunk.