In the Craftsy course on ruler work, Kimmy Bruner recommends using a foam brush to apply the chalk rather than the pounce pad. She says this will apply less chalk. Having too much chalk causes it to bounce around all over the quilt and into your face when longarming.
Pounce is an art term in this case, not a description of what you do with the product. One of the definitions of pounce is "a fine powder, such as pulverized charcoal, dusted over a stencil to transfer a design to an underlying surface."