I don't go into too many details when it comes to physically describing my characters. Part of the reason is because I think that no matter how I describe them, my readers are going to picture them in their minds in their own way anyhow. So I offer limited descriptions of hair and eye color and emphasize the use of words like, "Fit," "Athletic," "Muscular," "Voluptuous" and, of course, "Curvaceous." Though I do occasionally offer a cup-size when describing a female character's breasts.
I do love a woman with curves. The classic hourglass figure will always get my attention and many of my female characters are described that way with curves that don't quit. One notable exception was the character of Valerie in "Submitting to Angie" who I described as athletic and somewhat small-breasted but still a very sexy woman. The reason I described her the way I did is because she's based on a person that I really knew who looked that way.
Of course, only a handful of my characters are inspired by real people, most are just figments of my imagination. Though Christy in "Camping with Christy" was inspired by a real person, the character ultimately took on characteristics that were unique to the fictional character that I created and she wound up not really resembling, in my mind at least, the woman that inspired her.
My main male characters are usually "fit" and perhaps muscularly "defined" but their male lovers are usually described as "pretty boys" and sometimes "twinks" with an air of femininity about them since why else would an otherwise straight male character sleep with another man if not for the fact that he was pretty? Well, in the case of Greg and Alan, you've got two guys approaching middle age on fairly equal footing physically. Then there's the case of the simulant characters of Billy (a pretty boy) and Hank (a masculine, muscular specimen) in "Virtual Encounters" who will be revisited in another story.