Throughout history, men have used their personal pieces of wood as (seemingly) nonviolent battle devices against their fathers. However, perhaps no one else in history has used their personal piece of wood with as much of a full-on "fuck you" vibe as King Tutankhamun, also known as the source material for that Steve Martin video.
The new prevailing theory on such matters of wood, as quoted by esteemed literary journal Mirror, is that King Tut's "everlasting erection" was intended to make him look like Osiris, the god of the afterlife. The answer to "Why?" involves layers and layers of low-key wood comparisons, which is to say that Tut insisted on being buried with this particularly notable piece of personal wood just to piss off his dad. Tut's personal piece of wood, born merely of spite, reportedly stands at a sharp 90 degree angle.
In other words, hard-on. Boner. Chubby. Stiffy. King Tut was buried with an erection currently in progress, surely a bravery that shall remain unmatched for many centuries ahead.