I've enjoyed "showing off", otherwise known as exhibitionism, for more years than I can remember but now that I'm older I try to do it as much as possible for no other reason than it excites me. I'm athletic, and still am, completely smooth with a few piercings here and there that I feel is something to attract the gaze of anyone who might see me.
Showing off includes just being seen naked and also masturbating for anyone who enjoys watching, and you'd be surprised just how common that is.
I recently joined a nudist walking group and on one of the walks it was just me and one other who turned up, which was probably because the forecast which wasn't too good. But we walked naked anyway and at about halfway the other chap asked if I'd take a few pictures of him, which I obliged, and then I asked if he'd do likewise using his camera (I didn't have one with me) and that was a great opportunity to pose naked for pictures knowing that he was enjoying taking them. I positioned myself so he could get the best pictures of me and afterwards, and I was aroused by then, I told him I'd like to masturbate so we walked a little further to where there was a fallen tree where I sat down and spent a few minutes with cock in hand as he watched. I wasn't sure what his reaction was going to be but he was more than happy for me to masturbate and watch me ejaculate over myself.
Afterwards he admitted that it had been a missed opportunity for him and that he wished that he had taken up my offer to photograph me and take my cock in his hand to bring me to orgasm.
Masturbating totally naked, outside, and in front of a stranger is def showing off!