Possible Clues:

• Squash, squish or squelch
• Hit, as the gas
• Squish or squash, in a way
• Board
• Speed up for ages, then stop calamitously
• Squish with a shoe
• Use as a doormat
• Squelch, in a way
• No little dears will turn to get this underfoot
• Get under one foot of it (4, 2)