Yes just the taboo, and young body is pretty sexy, but the number one reason is that they make you feel so sexy!
I never would have persuded a young guy if not for my husbands "daring me to" (and too much alcohol :P ) but the respone I got made me feel beyond sexy. Knowing that you can still turn on a young cute guy is just such a confidence thing.
On top of that they are typically so sweet and sincere.
Sure, I know they get hard if the wind blows :) but that doesnt make it any less fun.