While claiming to have a headache is the stereotypical method for the human female to avoid having intercourse with her partner, the Lake Eyre dragon lizard has her own (and possibly more effective) methods of getting out of her "wifely duties". From here:

"When Lake Eyre lizards copulate, the male bites the female's neck, climbs on top of her, wraps his tail around hers and inserts one of his two penises."

Sounds kind of like human copulation so far. Well, with the exception of the two penis thing. That would definitely change things....but for the female lizard, the bites on the neck are less like the hickeys you may remember from your teenage years and more like a predatory animal attacking you.

"This can be hazardous to the health of the female, because when the males bite them on the neck they can pierce the female's spine, killing her."

According to the scientist in the story, the males do not give up and "try to force copulation and they harrass females all through the season." (this sounds like a frat party.)

To combat the unwanted attention, the lizards then throw themselves on their backs, which seems counterintuitive, but this makes it impossible for the males to "get lucky" with the females. Also strange is the fact that testosterone is believed to me the driving force behind the female's successful rejection tactics.