also: はなぢょうちん
noun
snot bubble
A bubble of nasal mucus that forms at the nostril, often seen in sleeping children or comical depictions.
赤ちゃんが寝ている間に鼻ちょうちんを作っていた。
The baby was making a snot bubble while sleeping.
漫画のキャラクターが鼻ちょうちんをふくらませて寝ている
The manga character is sleeping with a snot bubble inflating.