The plot never changes in an adult flick, but the titles often titillate a writer's senses much more than the screenplay itself.
Here are a few examples:
WEAPONS OF ASS DESTRUCTION
RIDING MISS DAISY
PUMP FICTION
MUFFY THE VAMPIRE LAYER
SATURDAY NIGHT BEAVER
PORN ON THE FOURTH OF JULY
A TALE OF TWO TITTIES
DONE IN 60 SECONDS
FOREST HUMP
GOODWILL HUMPING
PHALLUS IN WONDERLAND
Feel free to add from your collection.