I'm not sure where you have to give the shot, but if it's in the back part you can use a clear plastic tube a little shorter than your snake is long, and slightly larger around.

I found this site for an example http://freckleface.com/shopsite_sc/s...rylictube.html

They seem pretty expensive there, but I'm sure you could find something that would work. Heck it probably wouldn't even have to be clear and not too long. It will give you more control over the snake. Just put a cap on one end of it. I would drill some small holes in the bottom for breathing.

Maybe you can run with this idea and come up with something useful.