From The Martial Arts Encyclopedia

The Lay and Pray defense in MMA eludes to an inexperienced groundfighter's defense tactic of grabbing the opponent and hoping for a restart to get back to the feet. Many times this defense is employed by dedicated strikers when going against Ground and Pound or Sprawl and Brawl specialists, as the lay and pray defense is not as effective against experienced groundfighters as it is against others with little experience at this aspect of the fighting game.