Write it on your stomach: the paper will get confiscated at booking and cops specifically look for people with writing on their arms at protests and use it as evidence of premeditation. If you don't know a local defense attorney, look up the National Lawyers Guild number for your city.
If you're at a protest where there might be arrests, write a local defense attorney's number on your arm or on a piece of paper. If you're at UT specifically and don't have one or want to find one yourself, write this one: