You have extensively studied the art of grappling. You gain the following benefits:

• You have advantage on attack rolls against a creature you are grappling.
• Creatures have disadvantage on attack rolls to pin you 
  • If both creatures have the Advanced Grappler Feat, the one with higher level will get advantage on dominant positions
• You can use your action to try to obtain a dominant position within the grapple. To do so, make another grapple check. If you succeed, you and the creature are both restrained until the grapple ends.
• Within a dominant position you can use your action to try choke or maim a creature you have been grappling. To do so, make another grapple check. Creatures must have a neck and head to be choked and limbs with bones to be maimed. Disadvantage on choke or maim attack rolls against undead.
  • Choke - Creature must succeed a constitution save against your characters strength check. If they do not make the save they will become unconscious. If they do make the save, the status of the grapple returns to a dominant position.
  • Maim - Creature must succeed a strength save against your strength check. If you beat their strength save, roll a 2d10+ your strength for damage on the creature, then creature must roll a constitution save against the strength check you made to see if they are knocked prone. If you do not beat their strength save the grapple returns to a dominant position.