I'm gonna have to show you but i guess i can tell you but you might not understand. You're on the second or middle platform on descending then you get flow and double jump on block and jump again against the wall to get the teleporter but it's just a trick i would advise you not to do it or you'll lose the race it's slow just do the normal way.... it's just a neat trick i did once and some others have done it too i think.
Double Jumping is not hacking or lagging but a glitch. If you jump with flow, hit a wall and press jump again, you will sometimes do another jump. Some levels do it a different way. If you see someone Double Jump from a wall with flow, they just simply did a glitch trick. If they didnt use flow or hit a wall, then its most likely lag or less likely a hack.
not on every level like zipper, fuzzballs and funk (i think the name is funk...)
DEFINATELY CAN on funk anywhere there is a ledge you can double jump(not always useful but always can and zipper i do it all the time on the middle pillar, like if you're going to miss going over it you can double jump over it, not sure of fuzz though...
If you jump with flow, hit a wall and press jump again, you will sometimes do another jump. Some levels do it a different way. If you see someone Double Jump from a wall with flow, they just simply did a glitch trick. If they didnt use flow or hit a wall, then its most likely lag or less likely a hack.
You do NOT always need flow and can do it WITHOUT hacks or lag like on tubes and jumper(anywhere there is a ledge)
The game is designed in that way. If u just check how levels are made, gonna understand how double jumps and flow benefits ppl that use 'em. every level.