how to do the hover glitch?

i found the hover glitch as used in hover% category. a hover trick was known already before, but I found that it can applied to the whole run basically. unfortunately I have no idea anymore how to do it. but, I plan to come back to this game soon again.

But I saw you doing it. It makes you fly

Yeah you have to spam certain buttons basically, it's not hard to get, but I forgot how to approach the fat guy for example and which buttons exactly. The height is just determined by the length of the spam action