The concept is that you crawl out of your tent and down the hall and have some alone time with the stars overhead without the howling wind and unwelcome observers. Further, there is the possibility of bringing toilet paper, or if you want to be truly clean, use snow. I am not kidding, it works. Also crucial, buy outdoors clothes that are easy in, easy out if you want to have fun outdoors. Hydrate or Die.
Many women get headaches, fatigue and dizziness even on winter day trips.
They don't want to pee too much because it is unappealing. Get over it and drink a lot. You will, I promise, get used to the drill of finding a private place. It is more than worth not feeling sick. Good clothes means that you stay warm, safe and you feel more comfortable.