Carefully.
But really, as you’ll see, most of them have a gap to pee through, and a bigger one to poop. The ones with just a mesh aren’t really practical in my opinion, too much wiping up too often. But for most instances having some wetwipes by the loo will see you through the day.

The mesh is often on for lots of the photos but it’s a pain to pee through…
A bidet is a huge bonus if you’re seriously getting into chastity play though. Otherwise a quick shower rinse if things don’t go to plan is essential.
The truth is most female chastity belts suck. They are a hot concept, and can look amazing, but it’s just too hard to get a good fit and actually prevent you getting your fingers in, vs the annoying elements of comfort and using the toilet.
If you’re hugely into the idea then they’re definitely worth a go, but if you want it to be a real, long term option, you’re looking for a custom built, super expensive option, and even then it’s not easy.
Cocks however, cage those fuckers up goooood for about £35
Yep, us guys actually win that one, if having your family jewels locked up is winning (it is for some!)