It could be a non-action that occurs whenever the player doesn't take a free action to make it not happen at the start of their turn. The free action to stop it from happening may not be taken while dominated or charmed.

Have it strip ... first, all dominated and charmed conditions. Then have it strip one other condition of your character's choice, from a given list. Also include "under the effect of a spell" in that list.

Don't worry about it letting you strip self-inflicted exhaustion.