Sure you can.
A man can urinate into a lidded urinal in public just as discretely as a woman can breastfeed in public. All it takes is a strategically placed piece of cloth.
Both are natural body functions involving parts of the human anatomy that are not usually displayed in public. The only difference is that breastfeeding is Politically Correct in 2005 while urination is not. Back in, say, 1955, both would have been equally shocking at a City Council meeting.