Without condom is best by far. The sensation is much stronger plus you can feel her wetness.
I'm totally with the OP. I'm a natural exhibitionist. I have no problem walking around others naked. I don't care if I'm hard and dripping pre-ejaculate. It would be a complete turn on to be the center of attention at a CFNM event even though I'm not "Ken" or GI Joe.
I don't think there is an age criteria, but I would say if there is an age difference of 12+ years. I know many gals in their 40s who would consider it an insult to be called a cougar b/c it implies a certain lack of morals.