squish /(skwĭsh)/

squish

v. i.
  1. To make the sound of squirting water, like that made by the feet of one walking in mud or slush; to make a kind of gushing, swashing, or splashing sound; to move with such a sound.

squish

n.
  1. A sound like that made by the feet of one walking in mud or slush; a gushing, swashing, or splashing sound; a squishing sound.