is for Underwear.  The relative absence of butt shots in underwear ads reveals how incompletely our culture has eroticized the male body, which, unlike the female body, can never be the passive recipient of someone else's gaze, appraised and evaluated as a sex object, but is always frozen in genitally centered images so that the model can look back at the viewer, meeting his stare head on.  But perhaps just as importantly as the at best partial nature of the objectification of the male body, the refusal to turn the model around also represents a protective gesture, an act of coyness, an expression of discomfort with the traditional audience of underwear, the horny gay men who devour the model's body with their eyes, assessing the value of his attributes as if he were a slave girl on an auction block.  In the fiercely defended frontal nudity of the contemporary underwear ad, we see an implicit acknowledgment of the presence of the homoerotic gaze, a bashful awareness that the homosexual is looking, that it is he who sits in the front row of this never-ending striptease, relishing every bump and grind.