Anywhere really. prefer cover to avoid getting arrested again but that’s not always possible.
So long as people can’t see my wang in the open is fine.
Just check for electric fences and wind direction first.
The biggest issue i have with peeing whilst out on the bike is during the winter. I wear bib tights and the zipper only comes down to above the naval. So to avoid having to strip coat and base off, i usually try to haul the man hood over the undone zipper whilst dragging the bib as far down as possible.
This is never quite far enough and it seems to clamp a little on the pee tube trapping a little wee mid willy. Once fully relieved one can flop one member back into it’s normal place of rest and as soon as it’s there about an egg cup full of warm urine dribbles out.. 🙁