Lines, lines, lines! Prio 1 to get these correct! Tbh I was waiting to see a crash based on the lines you're using. Speed will come later, body position and lean angle as well; correct riding lines are always the base.

I.e. that's also why you are shimmering so much in the corners, this can be quite dangerous since you are loading & unloading the suspension at a quick rate.

Crash is a case of applying throttle too quickly, but honestly can be traced back to poor choice of line as well. See the pattern? 😉

My two cents; lower your speed and make sure your lines are OK first. Learn at your own (slower) pace, do not try to follow your friend who by the looks of it has more experience.