The Pat Sequence is a part from episodes that Leo has the team pat to power up rocket. After that Leo says he needs more power, so he has the viewers (kids) watching the show to Pat along with him to the beat. After that he tells the viewer to Raise Their arms high as they can and say "blast off"
Sometimes, instead of "Raise YOUR arms as high as you can, and say "Blast off!"" Leo says "Raise BOTH arms, and say "Blast off!"".
In the 2nd season, the Sequence is shorted a tiny bit.