Oh ok, I don't do speed running for this game so I didn't know.

You need dash to be able to do this, but what you have to do is (I did this on controller, but it is probobly possible on keyboard and mouse) put your finger on the jump button, then slide it over to the dash button in quick succession, then repeat. If you get the timing right, you can go quite fast

Are there any other sites i can use to share videos of speedruns, other than youtube?