Played in pairs.
Stand facing each other, about arms length apart. Legs slightly spread for balance. Arms up. Elbows bent. Hands palms out.
On a mutually acknowledged signal, lean towards each other without bending, until hands meet. Then push against each other's hands so that both players spring back to the upright position.
It's kinda like vertical push-ups.
Continue until you are filled with confidence at your mutual abilities. Then step back a bit and try again.
And so on, a bit further apart each time, until you've gone far enough, and you both are amazed at the combined length to which you can go in the name of fun.
Or you fall down.