The technique works as follows: He asks the boy to envision his escalating thoughts and fears in a cartoon-like 'thought bubble.' For example, a small sound at night leads to thoughts of a monster under the bed, which then grows to a full monster attack... etc. But he then explains to the boy that it's all just in his mind! Yes, the thoughts in the 'bubble' gets bigger and scarier... But all he needs to do is stick out his finger, and 'pop the bubble'...and poof, it's gone! This cute trick helps because it helps the youngster visualize that all those growing thoughts and fears, as real as they seem, are really only a figment of his imagination.

I thought to myself, "Hey, that's a great technique for Shemiras Einayim as well!" "Pop the Bubble!" Desire is aroused and the 'dimyonos' and the fantasies begin... They get bigger and bigger, seeming to be so real and enticing. But we've learned how it's all just in your mind... It's imagination. The fantasies are always exaggerations of the truth. As chazal teach us (Shabbos 152): אשה חמה מלא צואה ופיה מלאה דם והכל רצין אחריה. - (Shabbos 152a): "A woman('s body) is a barrel of excrement and her "mouth" is full of blood and yet all run after her". Rav Dessler and others describe how chasing desire is like chasing the elusive mirage in the desert... So here as well, all we need to do is to - "Pop the bubble!"