It doesn't sound like a good thing until you have tried it!

More detailed instructions in case you want to try it: https://www.thailandclimbing.com/chiang-mai/how-to-use-a-squ...

They wash their hands. What's so gross about them going extra lengths to cleanse themselves? Its not like they're going to then ignore their very hands, considering for many, its a religious law to be clean.

It seems like bidet fear but 10x. For no good reason.