プツッ

プツッ, ぷつっ, プツっputsu

adverb

1. (breaking) with a snap (of a thread, rope, etc.)
2. (ending) suddenly (of a call, communications, etc.)
3. breaking out (of a pimple, swelling, etc.)
4. pricking (e.g. with a needle)

Study it in Yanamino