It's not every day the K.N.O.T.L.O.V.E.R.S. Institute (Knife-ear Nonprofit Organization To Legitimize Organic Virile Erection Research & Study) has access to a live specimen for study, so this pair of very professional researchers are making the most of the opportunity.

...or in less-stupid terms: here's a picture of an elf having sex with a werewolf while her pal takes notes on how big the knot grows.