You must make the water inside swirl in multiple directions simultaneously to create enough internal pressure to burst the balloon.
Naruto (Dubbed) S02:E87 - Keep on Training: Pop Goes the Water ... - Tubi Naruto Episode 87
Naruto initially tries to pop it by just squeezing or putting pressure on it, which fails. You must make the water inside swirl in
Season 2 Episode 87 - Keep on Training: Pop Goes the Water Balloon! Naruto finally begins his training with Jiraiya. Naruto CapĂtulo 87 Parte 1: El DesafĂo del Jutsu Naruto Episode 87
Perseverance and the physics of chakra manipulation. đź“ť Plot Summary