I'd imagine that's because the spray touches her body in many places at once- causing a defensive reaction to "the unknown threat". Try narrowing the spray & aim for the face- more like a drinking fountain.
Another way I communicate with snakes is to offer something with my scent on it. (& make sure there's no scent of prey, haha!) You wouldn't want to use any fabric that snake teeth would hang up on too much- I'm thinking more along the lines of the sleeve (cuff) of a heavy jacket (make of densely woven fabric) that you impart your scent to first- rub it on your hair & hands. Many "enthused" snakes back off once they get our (yucky!) scent instead of what they're hoping for.
Just another way to signal to a snake. Or instead of your scent on that sleeve, use something harmless but repulsive to them. (like a bit of vinegar, etc.) Have fun-