foam up(redirected from foamed up)
To achieve a foamy, sudsy, or frothy consistency. The soap started to foam up once I mixed it with water.
[for something, such as soap or milk] to make foam or lather. Milk will foam up when it is boiled. The boiling soup foamed up and slopped over the pot.
To become more foamy: Shaving cream foams up when you spray it from the can.