i think i've figured out exactly how to get the grabs now. I'll post it, so don't read anymore if you don't want to know.
1st run; stomp at least one trick, and you'll get safety.
2nd run; stomp at least two tricks, and you'll get japan.
3rd run; stomp at least three tricks, and you'll get tail.
You don't have to do any advanced stuff, 180's are fine! And you can only get one grab per run. And you get them in that order. Sorry for spoiling it, but people keep messaging me about it!