itch.io

A woman is wearing the collar. I can give another hint if you wish or give the exact location, but I thought I would start with a minor hint first.

Added note in editing: I just checked something. The collar is in a room that you can drop an item and the scene will change. Collar stays in the room, but if did something to change the scene, the collar moves to being worn by a man. So worn by a woman if you did nothing in the room, wore by a man if added an item to the room.