I have drank about 1.2 liters of my own pee.
Piss must be well hydrated
For me I drink so much water, 2 or 3 water/diuretics bottles of 1.5 liters. I do it 3 to 4 hours after my last meal, preferably light - medium meal, foods that make you bloated and gassy like beans, broccoli, cauliflower, lentils, legumes, and chickpeas are a no no as they may trigger diarrhea which could ruin your session, so take an Imodium pill 1 hour before to prevent diarrhea, but consult your doctor or sexologist before.
1st bottle is for cleaning my bladder I wait about an hour and pee in the toilet,