I recall hearing Barrowman say somewhere that the reason he waves his cock around in public is because he thinks people shouldn't be so uptight about sex, but I think that's actually incredibly counteractive. Sex and nudity really are quite different things and for him to put his habit in a sexual context is actually just affirming everyone's worries about its inappropriateness. Sex is something people choose to be exposed to; he can't just expect people to loosen up about it by showing them his junk.