An app that allows people to charge members of the public to use their private toilet is being tested at the New Orleans Mardi Gras.
AirPnP - inspired by AirBnB, a service for renting out your property to travellers - said it offered a "legal alternative" to urinating in public.
Willing "entrepeeneurs" can charge a price to use their toilet, and must add details such as cleanliness and toilet paper thickness.
Users can rate their "pee experience".
The founders said the site was inspired by the yearly trouble the founders had when attending New Orleans's Mardi Gras festival, which has been running since 1837.
"During the Mardi Gras they routinely experienced the pain point of having no place to legally urinate," the Airpnp "About us" page explains.
"This problem is often solved by using what is known as a 'rogue pee'.
"If caught the person faces a weekend in Orleans Parish Prison. Yet this stiff penalty doesn't stop thousands upon thousands of 'rogue pees'. This clearly demonstrates the demand for a legal alternative."
Almost 2,000 people have signed up to use the app. At the time of writing, about 20 toilets had been added. All are in New Orleans, except one posted in Budapest, Hungary.
"Clean bathroom in our uptown home," reads one.
"Toilet paper and hand soap provided, of course. Large mirror for checking yourself out."
Another advert offers a "porcelain paradise" just off the main parade route, for $3 per visit.
The advert reads: "Imagine, you, gazing at passing floats. Now imagine you gazing at more floats just a few minutes later. Because that's all it will take for you to unleash your bowels in our frequently cleaned porcelain paradise."
The app's founders have a history of creating public-service-minded apps.
One of them, Travis Laurendine, has been recognised by the White House for efforts in "hacking" for a civic cause.
More than 10 million people have booked rooms using AirBnB, a popular alternative to using a hotel.
While Uber allows people to use their own vehicles to provide taxi rides.
These types of services - dubbed the "sharing economy" - rely on the principle that allowing users to easily vote on how good a service is will ensure high quality.