You can crush opponents when you grapple them.
Prerequisite: Str 15, Improved Grapple or Improved Grab, Improved Unarmed Strike.
Benefit: While grappling, if you pin your opponent, you deal an extra 1d12 points of damage in each round that you maintain the pin. You must hold your opponent immobile as normal (with an opposed grapple check), but you must also remain immobile, giving opponents (other than the one you're pinning) a +4 bonus on attack rolls against you (but you are not helpless). You do not gain this extra damage against creatures that are immune to critical hits.
Normal: You may deal normal damage to a pinned opponent by making a successful grapple check.