Let me get this discussion off the ground since the others are just wasting space.
Love to go up to public urinals--at airports, malls, home improvement stores (esp. Home Depot--great layout for this), movie theaters, sports/concert arenas, etc.--and drop trou below my muscled ass, show my throbbing hardon and stand back and piss or slowly stroke. Guys notice, watch, and sometimes join.
In gym, love to get semi or boned in open showers and sometimes stroke; kick back in steam/sauna and openly piss and/or slow stroke; will sometimes do the same at the pisser and have even stroked while sitting at the locker bench, esp. when in view of guys in the sauna.
In summer, I'll bate naked outside or in my car.
Nothing like the thrill of this sort of exposure. Some guys will get this, but many won't.