Being only in Day 2 of SR, I went to bed wearing only my PJs. Not too cool! For one thing, I was dreaming a lot and it seemed that with every dream, I was awakened by a night-time erection (called Nocturnal Penile Tumescence or NPT for short). Apparently, the penile stimulation was enough to wake me up, even in the middle of the night. My cock felt like it had a nice piece of steel running down the shaft, that’s how stiff it was! (By the way, a little research taught me that all healthy men have between 3-5 NPT erections each and every night, each one lasting perhaps 30 to 60 minutes each!) That is a lot of erections, guys!
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I am now used to wearing a “chastity cup” to bed and like the feeling it provides. The inside of the cup provides a nice, cozy “resting place” for my erect cock. Most of the “banana cups” (except one) are long enough to accommodate my erect cock nicely. The erect penis seems to be “at-home” there. So that’s why I continue to wear them to bed. And yes, on occasion I will be awakened by another NPT erection while wearing a cup.
PS Guys, you can’t stop these NPT erections no matter how hard you try. So you might as well enjoy them. I choose to wear a “chastity cup” to prevent masturbation and ejaculation. But as I described, there is another use for the cups: to accommodate the NPT erections and give you a reassurance that all is well within!
PS Although not well understood, the NPT erections do serve a purpose. They help “exercise” the flaccid penis and keep blood flowing to it to prevent atrophy. The NPT erections are supposed to be extremely rigid. That is why they can be uncomfortable by themselves, without some sort of support (either through a jockstrap or a “cup”. I’ve noticed myself that these NPT erections are usually much stronger than my “usual” sex-related erections and last much longer as well.
PS — “Learning Room”
(Courtesy of webmd.com) Other than blood and urine tests, a urologist may use these tests to determine the cause of ED or lack of erections:
Overnight Erection Test
Usually, men have 3 to 5 erections during the night as they sleep. Your doctor may use an overnight erection test to see whether you’re able to get an erection.
For this test, you will place a device around your penis before you go to sleep. It measures how many erections you have and how strong they are. A simpler version of this test uses a special plastic ring around your penis. If you get an erection, the ring breaks.
If the test shows that you can get erections, it’s more likely that the ED is caused by something mental or emotional.
Injection Test
An injection test is also called an intracavernosal test. Your doctor injects a medicine into the base of your penis that should give you an erection. If you don’t get one, you may have a problem with blood flow to your penis.
Ultrasound
Sometimes called Doppler ultrasound, this is another way to check blood flow to the penis. It may be used along with the injection test.
Your doctor takes a device that looks like a wand and holds it over your penis. It uses sound waves to create a video of your blood vessels so your doctor can look at blood flow.
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Source: https://www.aneros.com/blogs/with-npts-id-rather-wear-my-chastity-cups/