My cat has some kind of bladder problem and I need to collect a urine sample from it. The vet gave me this set of non-clumping kitty litter that should should let me use a syringe to collect a urine sample.

Also, the urine sample should not be too old. I have to bring it to the vet for analysis on the same day that it is collected. So I can not do it over night.

However, my cat does not pee on command. Obviously. So how should I go about that? Does anyone have experience with that?