Here you go ...

"The Pouch of Douglas is the extension of the peritoneal cavity between the rectum and back wall of the uterus in the female human body. It is also known by the names Douglas pouch, Douglas space, Douglas cul-de-sac, cavum douglassi, rectouterine pouch, excavatio rectouterina, and fossa douglasi. In women it is the deepest point of the peritoneal cavity, posterior to (behind) the uterus and anterior to (in front of) rectum. The corresponding region in men is the Excavatio rectoversicalis between the urinary bladder and rectum.

The Douglas pouch is named after the Scottish anatomist Dr James Douglas (1675–1742) who extensively explored this region of the female body. Three other nearby anatomical structures are also named for him - the Douglas fold, the Douglas line and the Douglas septum.

The pouch of Douglas, being the lowest part of the peritoneal cavity in a woman who is standing, is a common site for the spread of pathology such as ascites, tumour, endometriosis, pus, etc. "

So it is not a glamorous evening accessory, I'm sorry to say.

I wonder to what extent Douglas the Anatomist "explored this region of the female body"? He certainly left his little Scottish flag on a few internal structures in that vicinity.