^^this
The endo Yeti, looked like he was stiff on the bike, let his mass get pushed rearwards as the bike started front wheel up the ramp, then of course, as the front wheel drops, and the rear rides up the ramp, those stiff arms simply start to pull your mass forwards again, which due to the siff arms you can’t do anything about. Cue big OTB! (I should know, i’ve done precisely this!)
Gwinn starts very low, head near the bars, and stands up early, compressing the bike square into the ground in front of the ramp, then allows the bars to come back rapidly BACKWARDS towards him on the ramp, shortly afterwards absorbing the back of the bike up into his body (by bending legs and simultaneously extending his arms) This also has the effect of pushing the bike out infront of him, but cruically it occurs after the ramp/lip. In this fashion he de-couples the rotation of the bike during the ramp from rotation of his mass, and hence flies straight and true without under/over rotation.
Easier said than done of course!