Maybe I’m naive but is a 3 hour erection considered “normal”?
From the Mayo Clinic’s writeup on priapism,
Ischemic priapism can cause serious complications. The blood trapped in the penis is deprived of oxygen. When an erection lasts for too long — usually more than four hours — this lack of oxygen can begin to damage or destroy tissues in the penis. Untreated priapism can cause erectile dysfunction.
More information from an article in the National Library of Medicine:
While priapism is usually defined as an erection that lasts 4 hours or longer, physiological changes and microscopic tissue damage inside the penis typically do not start until about 6 hours after onset.[26] Permanent structural changes of the corporal smooth muscle tissue start to develop after 12 hours, beginning with trabecular interstitial edema.[26] Cellular damage begins 24 hours after priapism initiation with basement membrane skeletonization, increased platelet adherence, and sinusoidal endothelial destruction. Thrombus collections in the sinusoidal spaces and direct damage to cavernosal smooth muscle tissue leading to fibrosis and permanent ED begin within 36 hours.
Early treatment and detumescence generally do not result in long-term erection problems. If the priapism lasts longer than 24 hours, permanent damage begins, and up to 90% of such men cannot have normal sexual intercourse afterward.[27]
~Max
I don’t think they intended to imply a 3 hour erection is normal. 
I imagine the general case involves chemical assistance, but the point is that after 4 hours it starts to cause damage and needs medical treatment.
When I first started taking generic Cialis, it was an early personal concern, but it has been fine. Very fine. To paraphrase Jeff Foxworthy from one of his routines: if I have an erection lasting 4 hours, call your doctor? Heck, I’m gonna call everyone I know!
QFT. 
This is an example of a rare side effect being turned into a marketing tag line.
Interesting; TV ads have certain voiced warnings, but additional warnings in fine print, usually at the bottom. I’m guessing that there are FDA requirements for which frequency/severity ones must be voiced, versus left to the fine print.
So: curious if the “4 hour” thing was at a mandatory voice level, or if, as Marvin speculates, it was promoted for…reasons.
It was actually a couple of doctors who told me about the marketing aspects. Seemed like an open secret in the medical community, at least around primary care docs.
No, but at 4 hours 1 minute, it might explode.
On the stroke of midnight, perhaps?
I guess the question would be… what could/would they do for you at the hospital? Jam an awl into your dork to let the excess blood out?
If you value your existence, don’t feed it after midnight.
It’s always after midnight.
Hospital treatment of priapism may include medicine to help blood leave the penis.
Treatment may also include using a needle and syringe to release some of the blood in the penis. In some situations, you may need surgery to treat priapism.
I had a sleep apnea operation to open my windpipe that involved cutting my throat from ear-to-ear (I got a pirate-style bandage) and moving my tongue.
The stitching was not the best. I developed a giant blood goiter. The cure was sticking in a needle and withdrawing the blood. I think it took four large needlesful. One star. Not recommended.
You don’t see a doctor because something isn’t normal. You see a doctor because something is dangerous. Lots of things are abnormal without being dangerous.
Don’t Google it.
SNL alumnus Tim Meadows had a similar joke: Call a doctor? Hell no … Call more ladies.
I am legitimately curious if there’s a reason why somebody who isn’t a porn star would just have a 3 hour erection and that’s seen as fine.
I don’t know your gender or sexual orientation, but as a hetero guy I can think of all sorts of uses for such a thing.
Coat hook
Sundial
iPad stand