ummm, bad plan. If you want to engage safely in this fantasy, there are (clean) concoctions you can whip up that have the texure and smell of shit, more or less. I certainly wouldnt want to be involved, but neither would I want someone getting sick because of a kink they did not research fully before trying.

As far as urine is concerned, fresh urine contains ammonia, and is therefore pretty sterile at least at first, but not good to drink in large quantities (ammonia, yeh). Make sure the person urinating does not have any urinary tract infections/yeast infections, etc.

I don't know where to find this info online, but the reason I know it is because Dan Savage wrote about it in his column Savage Love a while back. Maybe you can find that column.

Anyway, defenitely not for me, but if you want to try this you need to be safe.