I love the idea of ownership marks (if you haven't noticed). My wife has several permanent scars from me as well as a nipple piercing.
This is why I enjoyed the manga/anime Loveless. It was before I really knew what bdsm was, or why I liked it. I knew I loved the idea of possession and permanent marks to show ownership. I just wasn't sure why.
The boy who's being pierced says something wonderful during this scene: 'The pain will be the evidence of a bond between us... When I see it, I will remember you."