A private room where a woman can relax, be alone and do whatever she pleases. Similar to a Man Cave.
My wife has turned the guest room into her own private She Shed. Its complete with angels, butterflies, incense, books, and flat screen TV. I am forbidden to enter!
Chapone: "I say, that lady over there is quite attractive. I think I shall endeavour to insert my penis in her!"
Chap two: "Wait, my amorous friend, and stay your hand. For I was there last week, and she has some serious Bread in the Shed!"