Genital piercing
One study from the University of South Alabama said that women with vertical clitoral hood piercings have more sexual desire and more sexual arousal and have sex more often than women without these piercings. During sex when the partners are facing each other, the partner's body (the pubic area, in particular) presses against the jewelry in the clitoral hood piercing, and the jewelry presses on the shaft of the clitoris and on the glans of the clitoris. The pressure and movement on the shaft and the glans of the clitoris feels very good for most women. (For some women, it does not feel good to touch the glans of the clitoris directly. The glans is too sensitive. It would feel like touching your eye. Those women might not like having a piercing near the clitoris. Those women could try using a sexual lubricant. A sexual lubricant is a slippery liquid. It can be bought at drug stores.)