Sex: How It Works

We've been doing it since we first walked the Earth. It gives us pleasure and it gives us life. But how much do you know about how sex works? Now, National Geographic Channel takes a fascinating look at one of the world's most popular pastimes: sex. Through gripping real-life stories and simulations, we journey from first times to playing the field, and all the way to humankind's ultimate goal, procreation. We'll learn anything and everything you've ever wondered about sex. Watch Sex: How It Works in HD free online now on SFlix with multiple servers and instant playback. Enjoy high-quality streaming of Sex: How It Works and share your thoughts in the comments below!