Sex for a female Lake Eyre dragon lizard is sometimes like going to bed with a man and a roaring chainsaw. The male lizard bites her neck before mounting her. If he sinks his teeth in with too much vigor, he can chomp her spinal cord and kill her.
So it's no wonder the lady lizards are choosy about sex.
From Washington University: “Fish Genitalia May Balance Attractiveness with Predatory Escape.”
The scientists found that female mosquitofish prefer the well-endowed male. Unfortunately for the males, larger genitalia impede a speedy getaway, making them more likely to be eaten by predators. Sometimes, you just can’t win.