Jen was the first to try this on me. A beautiful blonde, Jen used a white Reach toothbrush with an angled head to clean those hard-to-reach back teeth. Six weeks into our relationship, I found her toothbrush in the bathroom next to mine.

Sure, I'd already agreed to let her keep a change of clothes at my place. But a toothbrush displayed prominently on my bathroom wall for all the world to see was a different matter entirely. Like a male wolf peeing on a tree-trunk to ward off other males, Jen was marking her territory.

After my initial shock had passed, I was struck by the odd symbolism of it. Her white plastic Reach standing hand-in-hand beside my dark blue Oral-B. It looked a little too much like the bride and groom figurines on a wedding cake.

Suppressing a shudder, I yanked the toothbrush from its perch, hid it away in the medicine cabinet, and tried to put the image out of my head.

The very next morning, it was back. I hid it away again. This pattern continued for the next couple of days. It became an unspoken power-play between us. We never talked about it, but when either of us entered the bathroom, it was an unavoidable topic. Either the toothbrush was hanging there, or it wasn't. Either she was asserting her dominion over me, or I was refuting her claim.

Eventually I caved in and allowed the toothbrush to stay. Yes, I admit that I succumbed to a moment of weakness. But Jen was not just some random, voluptuous blonde I was banging on the sly. Frankly, Jen was the best sex I ever had.

For the next six months, I patiently endured her toothbrush. But before long, our relationship sputtered out. And when she and her toothbrush left my life, I mourned her loss briefly, taking what comfort I could from the fact that my life, and my toothbrush holder, were once again my own.