These are special attacks you can perform while grappled onto a monster. The parts you attack become wounded, making them more susceptible to damage for a period of time, and less likely to deflect your attacks. This should prove very useful when attacking tough parts of the monster, or if you're looking to break specific parts.
Weapon types play an effect on how easily the grappled weapon attacks wound a monster's body part.
Claw attacks you make when grappled onto a monster's head will change the direction that the monster's facing.
The Flinch Shot is a special move you can perform while grappled onto a monster's head. The Flinch Shot shoots all of your slinger ammo into the monster, sending it flying in the direction it's facing. If the monster hits a wall, it will topple, damaging certain parts of the monster, as well (and increased damage for parts that are wounded).