If you hold left while holding down B as SpongeBob goes through a loading zone you will buffer a bubble blowing slide to the left. If you hold right while holding down the B button as you go through a loading zone you will buffer a bubble blowing slide to the right. This is very forgiving. You can hold the inputs as early as you want when going through loading zone. I assume that this will work with all loading zones (unsure about doors, and it probably doesn't work with boss entrances), though I’ve only tested it on 5 loading zones so far, so this would need testing to confirm. They were all in Urchin’ to Fight.

You can also buffer a jump doing this. This could be useful in some levels such as Snow business, Clambake, Under the Boardwalk, etc.