Residents of the St. Pauli quarter of Hamburg, Germany took matters into their own hands by declaring “peeback time” after the frequent urination on walls by a steady stream of partygoers stunk up their businesses, playground, and alleys. St. Pauli’s Community of Interest organized a project to apply a superhydrophobic coating to walls in the area–some marked with warning signs, some not–that causes urine or any other fluid sprayed on the wall to splash right back at the perpetrators. The group hopes this deters people from peeing outside, though they don’t mean to be unfriendly to tourists.

The project has already had more than a wee effect on the area, as the campaign has gone beyond St. Pauli as it whizzes around the Internet.