I read somewhere that you straddle it until the only words the patient can say are Garp and good.
What, you don’t have any spoons?
I have no personal experience, but a friend once told me that this happened when he got an erection during the ultrasound that came with his category 1 aviation medical exam, in 2000. The nurse gave him a whack on the glans and that was the end of that. I can’t vouch for the veracity of this story.
Jeez, half the people in this thread can find out for themselves if being flicked with a spoon will deflate an errection, and no one is willing to try it? When thinking about what I’d do if I have a penis for a day while reading this book, science experiments was one of the first things that came to mind 
My mother was a nurse in the 1960s-70s and she says yes, she was taught this technique but she was also instructed if someone got “rambunctious” she could call for an orderly and let them sort out the situation. She also says she never encountered this problem and so has no practical experience and no good stories to share, at least not in this department, anyway.
This is what I heard anecdotally as a teenager in the early 60’s, from someone who supposedly knew the whackee. The nurse was all business and matter-of-fact about it, patiently delivering two or three sharp but mild whacks to the friendly weapon, which quickly got the message.
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One must get fluid out, not in. Irrigating with saline can help flush out clots if they’re present, but the fluid pumped in must still be aspirated out. Otherwise, increased pressure will accelerate the rate of penile infarct.
Whack my peepee, I tweak your nipple.
Fair’s fair.
And it is assault.
LOL! RN for 30 years, here. Never taught the “flick” thing (but I did hear of this anecdotally–it must have happened way before my school in the 70s, tho). Putting in a foley, you just ignored it. In order to really stop an erection (with patients with penile implants, etc., reasons to avoid erections), we were taught to use ammonia capsules. Just one sniff------
What I want to know is why an erection would need to be deflated. Use of a catheter has already been ruled out.
And I furthermore balk at the idea that nurses were told to intentionally inflict pain in patients, especially when other methods are always available. Every medical professional I’ve ever met has regarded “Do no harm” as important (whether it was in their oath or not.)
ETA: Stupid non-refreshing tabs.
Not a nurse but in med school we were taught to ignore and go on to another part of the exam, although I suppose a urethral swab might work too but I only do those if absolutely necessary as the male patients apparently don’t enjoy them too much.
Penile infarct?!?! Great, you’ve given me enough fuel for weeks of nightmares! Whatever happened to “Do no harm” doc? 
None. My friend was apparently quite happy about not having an erection while he was being probed.
Embarrassment?
Do you know that types of things a nurse has to deal with every day? An untimely erection is NOTHING compared to what they need to do daily for some patients.
:p;)
I know of a guy who suffered a neck injury and was paralyzed. During his long hospital stay, he would occasionally get erections. One day one of the nurses was kind enough to lend a hand and take care of it for him. It wasn’t like a porno fantasy, though. He explained that she wasn’t attractive and performed it in a very clinical way.
Heck, just saying out loud that you might get near the frank and beans with a pair of scissors would cause instant noodle.
I can imagine. I was assuming the supposed whack treatment would be to ease the patient’s embarrassment. To the nurse/doctor it wouldn’t be much of an issue, if any. But for the patient, especially a teenager or very young man, maybe the embarrassment would be too uncomfortable to ignore, regardless of the doc/nurse’s gender.
I’m sure glad it never happened to me. Yikes.
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Is this technique taught in nursing programs? Is it documented in medical literature?
Several nurses and their daughter(s), and patients have given their anecdotal experiences.