Tom made a stock and it's simmering the bones and the mirepoix of his stock a second time tom is creating what someone answer you so much

Tom is most likely making a Remouillage. It is French for "re-wetting." It is stock that was made from bones that were already used in a previous stock. It is also known as "Second stock." The bones would be re-simmered and fresh mirepoix added. The result of a Remouillage will not be as clear as the original stock and is a bit weaker. 

If it's a smaller child or infant, place one on the middle of the chest and on the child's back. (if it is a bigger child with enough room for two, place one on the upper right/your left of the chest, and one on the lower left/your right) the pads should never touch each other.