This is a method for locking a limb, (Hand or Foot to another object (other character, vehicle) While still having the ability for subtle, layered animation.
Maya Tutorial on how to lock an IK controller to another object and still have the ability to animate it while it goes along for the ride.
Group a Locator, Constrain the Group to the Object you want to follow, and Constrain the IK Control to the Locator.
Then you line up and animate the locator. Can Animated the Constraint Blend on and off, for it to follow or not follow. On the shape node can swap between multiple constraints.
Went fast in this tutorial (because it's on video(can re-watch)) & already went over slower with the class.
(Cropped, Contrast Enhanced, Volume Enhanced, Re-sized, & Compressed)