adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
whaa whaa; sound of a baby crying
Onomatopoeia for a baby's loud, continuous crying. Often used with 泣く or と.
赤ちゃんがヒーヒー泣いている。
The baby is crying whaa whaa.
夜中にヒーヒーという声が聞こえた
I heard a whaa whaa sound in the middle of the night.