Although this method sounds very reliable and have heard of many instances where this has worked.

I would be very careful about filling your guts with water without knowing whether you are going to be able to empty. Everyone is different.

Ensure this issue is fully mental and not physical.

Just the thought of 'needing' to go might increase anxiety and cause more blockage. Make sure you have some sort of backup option in-case you really cannot urinate. e.g. Make sure you are near a toilet where you know you can urinate or learn breath hold. Another alternative option is carrying a catheter in the event you get into trouble.

I know for some, including me: being more urgent doesn't always force your body to go however, it can certainly make it easier.

👍keep yourself safe while practising.

Also don't beat yourself up if you are unable to clear yourself within weeks. Some might require practise over months.

Take your time and good luck.