Blah
A blah is a vagina.  Queers and Australians (no relation between those too, of course. :p) typically refer to the vagina as a blah. When the word vagina is said quickly, it can sometimes be mistaken for the word blah.
Go stick it in your blah!

I told Brenton's mother to stick it in her blah, but she didn't hear me.

Last week, I got Stacy to take her pants off and show me her floppy blah.  It was nasty.