I know once upon a time ago I had a DM who imposed penalties to the male characters if they were fighting naked female monks. They were just so enticing for our characters to watch sway and jiggle that we had -4 to everything (attack, saves, AC, etc). If you were playing a female, however, you might only have a -1 to everything because of the sheer shock of seeing someone degrade themselves like that to gain an advantage.
The reason I bring this up is in an upcoming adventure path, the PCs will be fighting topless mariliths, and their hair is up (as per the picture) so everything is shown. The group's split pretty evenly between men and women, and one of the PCs is playing a perverted gnome (go figure) and would likely be enthralled by this. So, is there some kind of rule somewhere? Maybe a template? I've got access to Enticing and Fascinating Gaze ones, although one's literally a gaze attack, and the other is more befitting of sirens (you're compelled to not attack and just walk closer to them).