If the following excerpt touches a nerve, you should read Chapter 3 of Marcie's Visit To Her Grandparents. It's about a 15-year-old boy and girl who barely know each other being aroused almost beyond self-control and put together for the natural conclusion.
It was purely for sport. She couldn't get pregnant. They weren't in love. It was two horny kids being mated by their families, not unlike putting animals into a pen for breeding with spectators witnessing the indignity inherent in copulation.
In the final throes, it's never elegant or gracious, regardless of the species. It's raw emotion and self-abasement in pursuit of ultimate satisfaction. It's moaning, grunting and lurching as partners descend into animalistic behavior for desperately needed sexual release. Afterward, their genitals were testimony to their indulgence.