natures suitcase
The vagina is referred to as Natures Suitcase only in situations of concealing some thing they don't want to be found by a third party, aka the "police". This area can hold an enormous amount and is highly versitile, but like any suitcase, a dog can sniff it out and a warrant is needed to open it.
Jenny, we are getting pulled over by the cops, hide my drugs in your natures suitcase!