Sometimes I am out at night driving or walking around and a clean bathroom isn't always available. I used to get drunk at rack daddy's at riverside and pleasant valley (rip) and as soon as I would leave the lot, I would have loose bowels. I would have to defecate in the ibc parking lot at pleasant valley and cesar Chaves or at the car wash just south of Riverside.
I used to hang around the Hancock center (shopping center with heb) at 1000 e 41st almost every day. But sometimes it was late and couldn't make it to the heb bathroom. I would have to go to public stor age across the street and go behind their dumpster. Be careful where you step because other people would go behind the dumpster as well.
There is a parking garage at 183 and Anderson that I've used before as well. I always carry a roll of toilet paper in my car. You always find a use for it.