btw this was easy mode, which is wayyy too easy. i'm gonna go try hardcore mode right now.
to underslide, flip your board and right when it's upside down grab and hold the right bumper.
ALSO: there are a few really dope jumps if you take the lessons at the beginning, finish the challenges, and go around that complex. there are a few different jumps good for rodeos/corks/assorted flips.
so try that and have fun! i really like the jump with the QP after