I'm no expert but my opinion I don't think it's necessary to give your snake a bath unless of the following reasons:

1. It has a plugged cloaca and you need it to pass a bowel movement (rare).
2. It's an absolute mess (climbed in and all through feces). Even in this case I would probably try to wipe her down before I put her in a tub.

I find that if Valentine is stressed the best thing I can do is leave her alone until she relaxes not man handle her into a bath lol