Don't bother. Because :
1. It's annoying to have a lens cap flapping around when you are trying to shoot, esp when wind is blowing and it flaps around alot.
2. The sticky part will fall off, and you will end up losing your lens cap.
When you pull your camera out of the bag with your right hand, just use your left hand to quickly remove the lens cap and stuff the lens cap into your pants left front pocket. Always put it in the same place, and after a while, it becomes 2nd nature to remove the cap from the lens and put it into your pocket. And if you always put it in the same pocket, you'll never lose it.