Ok, I in no way advocate this, but I've been reading The Selfish Gene by Richard Dawkins, and within the 1st few pages he writes this, which I found hilarious. He's talking about how female praying mantises eat the heads of the males they copulate with...

"It might seem most sensible for her to wait until copulation is over before she starts to eat him. But the the loss of the head does not seem to throw the rest of the male's body off its sexual stride. Indeed, since the insect head is the seat of some inhibitory nerve centres, it is possible that the female improves the male's sexual performance by eating his head. If so, this is an added benefit. The primary one is that she obtains a good meal."

Hee hee!