Whip cream aid is a dry, powdered commercial product used to stabilize whipping cream to help it hold peaks and keep the whipping cream firm. Use 4 oz of product per 12oz of whipping cream.
If you don't have either of these whip cream aid products you can make your own by substituting:
Dextrose, modified food starch, sugar, carrageenan, calcium saccharate, calcium oxide, artificial flavor.