Sponge-Gliding is a glitch activated by slamming into specific areas with enough speed. When active, SpongeBob's slam animation isn't allowed to finish, and whatever momentum Sponge-Bob had when the glide was activated is stored until the glide ends.
When SpongeBob's feet touch the ground the slam animation completes and the Sponge-Glide ends.
The momentum required to activate a Sponge-Glide can come from one of two main sources: Damage Boosting or Cruise Boosting. If a Sponge-Glide is activated with Cruise Boost momentum, the glide can be steered left and right.