Let's face it, the very act of sex is weird. And gross. And the reason you exist. And the driving force behind the world's technology. Human beings have developed some very strange habits, and it's easy to look at something like, say, nasolingusts (nose lickers) and wonder, simply: why? But the science behind bedroom practices is actually fascinating. The oft-repeated "Rule 34" states that for every action there is an equal and opposite adult version of that somewhere on the internet. If that's so, then Rule 35 states that for every quirk and preference, there is also a team of scientists studying that exact quirk in a lab.