Alright, so kissing feels awesome. But other than getting that pleasurable sensation, do we know why we do it? This video will drop some knowledge on us!

The video above from It's Okay To Be Smart, Joe Hanson gives us the lowdown on the science of kissing. He explores why humans do it, what some of the factors are when it comes to kissing and the different ways people kiss.

Kissing is described as an odd human behavior, because it's essentially rubbing our open mouths against each other. But this action triggers something in the pleasure center of the brain and feels awesome. But where did this action stem from? Some scientists believe that when humans started to walk more upright, the lips became a sort of indicator of fertility. Studies have shown that dudes are attracted to fuller, redder lips, which is akin to how some simians are attracted to big, red bottoms.

In order to test out compatibility with each other, two people kiss and can kind of gauge if they'd be suitable matches for one another, mostly through smell. In Claus Wedekind's famous "t-shirt" study, a bunch of t-shirts worn by different men were presented to women. The women then picked which ones smelled the best to them. In most cases, the women picked smells of men with different immune system genes than their own. So a kiss, as this might suggest, can help you pick your partner.

Watch the video above to learn even more about kissing and don't forget to rain down smooches on that special someone this Valentine's Day! And every day, while you're at it.