I was always intrigued by this description of how the men dressed:

With them came a man dressed in a long purple robe, full at the shoulders. When he walked the robe flared open, from the waist down. One could see that beneath his robe he had on some sort of tights, which covered his legs and thighs but left the sex exposed. It was the sex that O saw first, when he took his first step, then the whip, made of leather thongs, which he had stuck in his belt.

The posted pic does not do justice to the prose…

If the costume we wear in the evening - the one I am now wearing - leaves our sex exposed, it is not for the sake of convenience, for it would be just as convenient the other way, but for the sake of insolence, so that your eyes will be directed there upon it and nowhere else, so that you may learn that there resides your master, for whom, above all else, your lips are intended.