In the Metro Kingdom there's a very easy to fund skipping rope shallenge. Get 30 jumps in a row and a Power Moon for you. Once done (it's not that hard), the bloke next to you says something like "I don't think anyone can get 100 jumps in a row". You all know what that means. Mario has to get 100 in a row for another Power Moon. But how? After 50 jumps, the speed of the rope is so fast that Mario actually risks double jumping. This double jump actually is what makes the 100 jump challenge very hard. You don't know when you'll double jump and when you do it kills the run.
A double jump in this case is basically the 2nd jump of a triple jump. It's higher than the normal jump.
There is a solution to this. I thought of it on my own, but I'm most likely not the first in the world to have thought it up.
Get on the scooter and do the 100 jumps. It's tough to get started and in the right place on the scooter, but when you've gotten yourself in, getting the 100 jumps is much much easier. There's no worry of double jumping on the scooter and the low jump (short A press) is quite low and consistent.
I ended up getting 173 jumps on on the scooter before I gave up and let myself be hit.