My back yard borders a fairly busy county road, and the front yard is a cul-de-sac with an elderly lady that likes to keep an eye on me, so my backyard whizzing is limited to late night when I can see headlights a ways off. But every now and then, I piss on one side of the tree while the dog waters the other side.
Back in HS I took a wilderness canoe trip in southern Minnesota. Even the girls were practicing writing their names in the sand. (That HAD to take some acrobatics...) Couple of us almost got into trouble the one day we went in to town...the urge hit, walk up to a plant in the middle of main street and reach for the zipper when you think "Wait... I probably shouldn't do this here...."