If you're stuck in a desert you won't be able to pee due to dehydration. Even if you manage to, you absolutely should not, it will be a concentrated toxic waste that will only cause more harm.
The second anon has much better idea. Chugging gallons of beer will fill your bladder pretty quick, so your body will try to get rid of excess fluid before all the waste gets into it. That way you can have a lot of pee you can enjoy drinking without poisoning yourself.
Stay safe bros