Moving with a lot of water or mud on the ground.
Slushing can be messy and wet. It can also be fun to play in.
Examples:
The kids are slushing in the mud.
The river is slushing over the rocks.
She is slushing through the puddles.
The dog is slushing around in the water.
The rain is slushing down the street.
I love slushing in the rain!