If you see a guy with an obvious hard on trying to hide it or act like he doesn't, would you tease him or do something to him or ignore and leave it?
It all depends on whether or not I'm attracted to him and want his attention, or if I have some compelling reason to watch him suffer, and twist in the wind.
If he was attractive I might approach him and see if we could find a way to a solution
Or if there was no sign of a vibe I would just leave and let him find his way.
I'm not sure about the circumstances leading up to him having his hard on, the location or who else might be witnessing this situation!
I mean if I know him, like him a lot and most importantly I'm the inspiration for his rigid appendige then I might glance at it, blush and hope he makes a move on me.
If it's some random guy with a random hard on in the street or anywhere else for that matter I would act like I hadn't seen it.