This all sounds like someone letting their fantasies run loose without thinking about the consequences. Any grass in an urban space is likely to carry all sorts of germs and parasites from dog and cat faeces which you really, really don't want to ingest. And licking toilets is fine as a fantasy, if you're into that, but nobody with the slightest grip on reality should be ordering you to do it for real.

Your Mistress needs a reminder that power brings responsiblity.