The purpose of this was to humiliate the princess by exposing her beyond just her body, and also symbolically showing the irony of a nearly-naked fertile woman being forced into a sexual relationship with a male who could not impregnate her.
The crescent moon shape of the plates was symbolic of the human female menstrual cycle, since a crescent moon only occurs once a month, which is very much like a woman's menstrual period. Her red skirts were also a similar color to human blood, symbolizing her menstruation. While the front plate concealed Leia's womanhood, the design symbolically exposed her deeper than her vulva. For Jabba, this represented her femininity and her complete sexual availability to the Hutt master.
Leia's PerceptionEditAs a royal woman, Leia was raised in a socially conservative atmosphere in which a princess was demure by nature. Wearing gold plates etched with depictions of her ovaries and uterus humiliated her. Leia hated her skirt plates, both for what they didn't cover and what they symbolized. Leia disgusted by the plates as they had the designs of a woman's anatomy engraved on them; it was a symbol of her femininity, as well as her royal status. She also hated feeling the cold metal plates rubbing against her nakedness underneath. The idea of wearing an outfit with a uterus and ovaries on it was embarrassing to her because they symbolized her status as a chaste virgin and her female fertility.
Leia also hated the back plate that covered her buttocks, since it accentuated her rear end and drew attention to it from males. The rounded bottom was also very uncomfortable to sit upon, since it was made of solid gold and she was essentially sitting on an unbalanced metal bulge.
The idea of wearing an outfit with a uterus and ovaries on it was embarrassing to her because they symbolized her status as a virgin by displaying a hymen showing she was untouched by a male and ovaries showing her female fertility, which was important to many females of many species. As a conservative royal woman, this humiliated her beyond words. The two ideas displayed right over her vagina embarrassed her, since it displayed a very private fact about her as a woman that would normally be hidden from view, even with stark nudity.
The plates also left her sides exposed, baring her flanks for all to see. This exposed more of Leia to the world than she was comfortable with, as not only her breasts, stomach, back and legs were exposed, but now the supple cheeks of her butt and smooth curve of her waist and hips were also bared for all to see. The rigidness of her skirt plates meant that while she was moving, there was no way to ensure that the skirt plates did not slip out of line and expose part of her even more, which often gave the throne room even more of a view of her nether regions than she was already comfortable giving. (see Leia's Skirts).
Jabba's perceptionEditAs a royal princess, Leia was very protective of who she exposed herself to. In response to this attitude, Jabba forced Leia to wear nothing but gold skirt plates to cover her vagina and buttocks to humiliate her and display his dominance over the enslaved princess, with her internal sex organs engraved on the front to show her true purpose in the palace.
Jabba also refused to give the princess any form of underwear beneath the skirts, with several reasons behind this. The first was so that her legs could move freely while dancing and reduce the chances of having to clean the outfit from sweat.
The other was to leave Leia more accessible so that he could enjoy her womanhood whenever he wanted. Another was to leave her dependent upon Jabba whenever her menstrual period came, since she was not allowed any pads or tampons, not that they would stay there effectively.
But most humiliating of all was so that Leia's intimate regions could be exposed to the crowds at any time, revealing her most private body parts to the crowd around her. Jabba knew this would degrade her and kept her bare, forbidding her to wear any panties under threat of being stripped entirely nude and whipped.
The lack of underwear left her completely bare underneath and vulnerable to others seeing her vagina when she moved, shifted, and (especially) danced. He loved seeing Leia humiliated and trying to cover her intimate parts to no avail, and would often reach beneath the skirt or undo them to expose Leia to the crowd, showing her that there was no chance of privacy or comfort for her in the palace.