There are few topics that can evoke such widespread and intense anxiety as penis size. Just about every man — regardless of the actual size of his penis — worries about being too small. Here’s what you need to know about penis size, and what to do if you’re afraid your penis is smaller than “normal”.

Every now and again, Lifehacker asks a medical professional to explain the weird things that our bodies do. Or could do. Or might do

In this way, your thirst for weird bodily function knowledge is sated - without besmirching your search history. Let's get started.

The morning penile erection, or as it is medically known, “nocturnal penile tumescence”, is not only an interesting physiological phenomenon, it can also tell us a lot about a patient’s sexual function.