Use randomiser to determine what you are using to hold all the balls e.g in one hand, two hands, mouth, pockets, armpits, all over your body any way you can
Players have 60 seconds to complete task
Players must hold balls in position for 3 seconds to qualify
Winner is the player with the most balls held in position
Variations
If playing in teams, team mates could be the ones stacking the balls on their partner