What do you do if someone defocates on your chest?

Its a good Idea to clean it off. Feces contains all kinds of bacteria that will cause nasty infections if you get it on a sore or cut. You can contract anything from a Staff infection to Ecoli. Wash with soap and water, and if you notice any rashes or redness then see a doctor immediately. Common antibiotic ointment may treat some bacterial infections, but others will require specialized antibiotic ointments or medication.