I went to Tseun Wan yesterday & found a large public toilet by one of the walled garden parks Unfortunately, there wasn't anything on display of great interest. So I headed back there again early this afternoon - and there was plenty to choose from.
Here's the Google Maps image:
It's at 67 Tseun Wan Market Street and in front of a walled local garden/public park.
Having almost no Mandarin or Cantonese and it being a very Chinese area, I had to make do with some fairly subtle gestures. However, it didn't take much in the way of signaling or encouragement when I spotted what I was looking for, being a reasonably discreet, middle-aged man with a lot of foreskin. He followed me into a private stall - and after some very brief foreplay, I slid back his foreskin with my lips. He obviously found it very erotic....and was done in about 30 seconds.
I went back to the urinals briefly, but didn't find anything of real interest.
And I do have HKG here again tonight - so I need to conserve my energy.