Here's a couple from Australia:
* She can talk under cement (think Lashawn)

* As ugly as a hat full of nuns' cu*ts (definitely not in polite usage)
* Bumping uglies (having sex)

* Do I look like someone who gives a f*ck? (used sarcastically, meaning "I'm not interested")

* Flat-out like a lizard drinking (very busy)

* Trouser snake (penis)

* Map of Tasmania (vagina)

* Point Percy at the porcelain (urinate - male)

* Technicolour yawn (vomit)

* Moon tan (pale complexion)

Kerry