Morning glory. The early riser. The ol' ante meridiem bedsheet tent-pitch. Nocturnal penile tumescence. Whatever you call it, much of society has experienced morning wood in some capacity — but why? How? How does it work? Don't pretend you're not curious.

In this quick and dirty video, AsapSCIENCE's Mitchell Moffit and Gregory Brown do a bangup job parsing out the hard science behind early morning hard-ons. For instance: did you know that a full bladder, of all things, can contribute to an erection? BOOM. Now you do.

[AsapSCIENCE]