[album=large]146272[/album]I've been wearing tights while winter running since the 1980's and usually go commando underneath. When I gets really cold, I'll wear a thong for added warmth in the crotch. They also enhance the bulge and show no "panty" lines which is nice.
Since my flaccid cock is average in size, there's not a lot of flopping around but occasionally I'd catch an eye, male or female, checking me out as I ran past.