You may not have given it much thought, the awesome things that happen to your body right before and during an erection. Who the hell could think straight with a boner, anyway? Thankfully, the guys from Men's Health USA managed to, um, get a hold of the situation, and they've come up with a video that explains how exactly your whole body gets its shit together just to make manoy stand up.
According to the video, men's sexual arousal is a complex process that begins in the brain. The stimulation causes nerves in the brain to send chemical messages to nerves in the penis, telling the penile blood vessels to relax so that blood can flow freely into your dick. When the high pressure is trapped, it causes the penis to expand. You get a hard-on. And the rest, they say, is history.
Now get your hands off your crotch and watch the video below instead: