So for your vertical behind the back pass, you're going to start with your vertical hand roll in front of you. You're going to rotate your body, so that the hoop is beside you. Your thumb is up, like a handshake. Thumb is up, palm is forward, to keep the hoop from coming up your arm.
Then, when the hoop touches your palm, you're going to grab it. And then you're going to rotate your body, so that your back is to the hoop. Rotate your arm forward. Allow the hoop to fall down behind you, and then you're going to grab thumbs together, palms up. Pass off, and then you should be in reverse hand roll on the other side.
So if we try that again, in slow motion. It's on the side of my body, grab, pass, hoop is down. Hand off, under hand, thumbs up and then reverse.
So then let's try this on the left. Forward, grab, pass underhand, and then I reverse on the other side.
That's how you do the behind the back vertical hooping pass.