A character with this trait wears or has worn a choker.
A choker is a close-fitting band encircling the neck. Chokers can be made of a variety of materials, including velvet, plastic, beads, metal such as silver, gold or platinum, leather, etc. They can be adorned in a variety of ways, including with sequins, studs, or a pendant.
This also includes collar-style chokers (typically leather bands with buckles) which are worn as fashion accessories and detachable shirt collars.
Example 4 (Detachable Shirt Collar)
Detachable Shirt Collar