Two days ago I was watching a show on Animal Planet called "Monsters Inside Me" and one of the cases on the show was of a woman who was being infected with bed bugs. That's when I first heard of "traumatic insemination."
Traumatic insemination is a mating practice that takes place among some species of invertebrates (including bed bugs and even some spiders). The process apparently differs slightly depending on the species, but generally involves the male piercing the female's back and injecting sperm into the abdomen.
Of course I had to do more research on this topic and came across this piece (including pictures that may be NSFW) about male seed beetles whose penises are covered with spikes that injure the females. It also discussed the violent sexual practices of some other species which made me cringe while reading.
Despite explaining how the female seed beetle has developed some defenses "so that the damage inflicted by the males doesn't affect her too badly," my new knowledge of the violent mating practices of some species was rather disturbing because it seems that females of many species are no strangers to sexual violence.