I like having pepper available when I'm riding my bike as I'd much rather spray a dog than shoot a dog.
That said, getting to a pocket carried can of OC is not easy when on a bike, and is doubly hard when going fast, trying not to get bit.
I asked Tom at Dark Star Gear for a solution a while back, and this is what he came up with:
The holster bolts where a second bottle cage goes, and the can of pepper is retained with shock cord. The draw is very fast, and replacing the can in the holder is not terribly difficult. The holder is very secure.
Thanks, DSG!