Oh :P that one you have to jump right as you hit the trampoline or slightly after. You can usually tell if you hit it because you’ll get a massive boost, otherwise you’ll either jump bounce without any extra propulsion, or hit a funny landing and completely fail.
It’s very tough to get the timing right and it gets harder the higher up you get. It’s a bit hard to tell when to actually hit it but I recommend using the sound as a cue.