Humans, far more than any other related species, have sexual intercourse for the pleasure they derive from it. In the human context, sex is therefore a pleasurable act which if done responsibly is all fun and games, and if done thoughtfully and accurately, also helps in conception and propagation of species. Seems innocuous, doesn’t it? If you break it down in this way, it appears to be no more than what it is: a basic bodily function and need. No different than breathing, growing hair or sweating.