Thick foam pumps out of the machine into the pit for everyone to dance and play in. The foam machine is placed at the back of the inflatable foam pit and pumps piles and piles of thick luxurious foamy bubbles into the pit. Once the bubbles pile up and the pit is full,it is time for the fun to begin! The foam *can* stack up quite thick, The foam is an all-natural hypoallergenic product similar to a bubble bath. so if you are hosting a party for smaller children, the foam pit is best choice.