adverb taking the 'to' particle
sloshingly; swishingly
Mimetic word describing the sound or motion of liquid sloshing or swishing, often in a small container or the mouth.
彼は口の中で水をくちゅくちゅとすすいだ。
He swished the water around in his mouth.
ペットボトルの中で水がくちゅくちゅと音を立てている。
The water is sloshing around in the plastic bottle.