collision mechanical interference without force interaction

Does anyone have an inkling how CharacterController is able to provide spatial exclusion in a way that "does not react to forces on its own and it does not automatically push Rigidbodies away".

I'm working on a jousting game and I want to procedurally control the lance on my model, but I'd like to prevent it from passing through my avatar's shield, or through the horse's head for example.

I've found this isnt doable with colliders + rigidbodies because the impact causes one rigidbody object or the other (at least one must be non-kinematic to register a collision and have spatial exclusion between colliders) to tumble away.

I have a gimp method which involves capturing the previous frame's transform for the lance, and then undoing it if you get an onCollisionStay call, but then you get this jerky back-and-forth in the model.

Here's to hoping this is a solved probem!