"It's where you hold stuff, silly," Susan told her, as if it were the most obvious answer in the world. "You don't wear clothes, so you use your vagina like a purse or backpack. You've always used it to hold stuff in, ever since you were little."
Jennifer felt a sudden, if mild, weight in her lower belly, and had the realization that it was composed of basic daily purse-type items: lipstick, cell phone, keys, etc.
"Actually," Susan continued, "it's pretty useful, since you can store a lot of stuff in there, and it never shows or hurts you. It's like a bottomless purse, or something. You always told me it felt nice keeping stuff in there."
Jennifer felt the weight lessen, as it was replaced by a slightly erotic, pleasantly full sensation. She realized that, actually, this was rather nice after all. One thing did concern her. "What happens when I have my period?" she asked.
"Oh, you only have those when you need to, you know that," Susan told her. Jennifer breathed a silent sigh of relief; at least THAT part of her life would be a little easier from now on. (At least, she hoped it would.)
"So..." Jen started to ask.