Traumatic Insemination

The Turbellaria flatworm was one inspiration for the post Sugar Bugs, and also for the mated pair forming the 'gy' in the site logo.

Many other species engage in this practice.

"The evolutionary origins of traumatic insemination are disputed. Although it evolved independently in many invertebrate species, traumatic insemination is most highly adapted and thoroughly studied in bedbugs, particularly Cimex lectularius. Traumatic insemination is not limited to male-female couplings, or even couplings of the same species. Both homosexual and inter-species traumatic inseminations have been observed. Traumatic insemination has been likened to human sadomasochism, stabbing, and rape behaviors. However, such coercive sex practices are common in nature and provide sperm competition, enable bypassing the mating plug, and overcome female resistance to being mated." -Wikipedia