Why is it that we, men, frequently have an erection when we wake up in the morning? If the matter has already been touched upon by Dopers in the past, my apologies: just…point the way 
I believe that men often get erections during REM sleep. If you wake up while dreaming or immediately afterwards, things haven’t quite subsided.
Also, sexual hormones peak in the morning.
Mastery is not perfection but a journey, and the true master must be willing to try and fail and try again
I, too, have read that this occurs during the R.E.M. phase, which usually closely precedes the moment you wake up. But what relation is there between R.E.M. (dream) and the erection, unless any type of dream (be it erotic or otherwise) produces this type of response?
‘touched upon it’ & ‘point the way, eh?’
Lots of reasons, full bladder, sexy dreams, naked woman[s] next to you.
Didn’t some researcher conclude men have around 40 erections per night? You know they have a machine,a penisioglometer [can’t speel it of course], put it around the penis and it informs whomever that who ever its attached to is getting an erection.
You remember them if you wake up having one, which most do cause they have to wake up eventually. I believe some guy did a famous photograph called ‘teenage lust’ and it was a teenager sleeping and having an erection. Gotta watch for cameras.
Hmm, I don’t know why or how, but there is an amazing morning wood every morning. I can’t remember dreaming about anything. And I do wake up alone…
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Adults (and I assume this to mean anyone over the time of puberty) go through an erotic sleep cycle each night. This is marked by a flush of hormones, and increased flood flow to the genitals and, in women, the breasts. This doesn’t mean that you’ll necessarily have erotic dreams every night, but rather that your body goes through this physical cycle.
“I guess it is possible for one person to make a difference, although most of the time they probably shouldn’t.”
It’s there, all right. But most of the time I’m not really in the mood to use it. I just wanna go pee.
Now, AFTER I drain my bladder…
Peace,
mangeorge
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Thanks,
mangeorge
Exercise! Or could it be just stretching?
It really is a pain and conficts with urination. After an extended night of drinking, the next morning I have to go really bad and the erection just will not go down, even if I think nothing but baseball.
So I use the ten feet away from the toilet approach and hyperbolically get about 50% into the bowl.
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I like your mastery of imagery, beeruser
And God help the man peeing with a morning wood/split stream combo. That’s why those magazines in the rack near the toilet always get wrinkley.
The way I heard it was that the kidneys keep working as you sleep. And of course, as the kidneys work (especially after a beer blast or something) the bladder fills. Well, the bladder is somewhat similar to a balloon, in that it enlarges as it fills. Sometimes it gets large enough to nudge the prostate gland, stimulating that enough to cause our friend, the morning wood. I won’t discount the added effect from dreaming about Claudia Shiffer, but I think it’s mostly due to physiological causes.
Ranger Jeff
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Ranger: the “bladder theory” would account for a very partial number of instances in my case. More often than not, I don’t especially feel the need to urinate when I wake up, but there it is nevertheless…
Beeruser: one way of solving your problem would be to let the “feminine side” in you take over, if only temporarily, in the anonymity of your bathroom 
I see you’ve never tried to urinate sitting down with an erection.
“I guess it is possible for one person to make a difference, although most of the time they probably shouldn’t.”
Jophiel: Needs a bit of manipulation and dexterity, but it CAN be done
Yeah, but it gets all wet.
Peace,
mangeorge
Thanks for the advice, omniscient. I’ll try the feminine approach, although I think it might be painful…
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You’ve got to go a little beyond the merely feminine and also bend forward sharply. Pretend you have a nice book to read right between your feet.
Not painful, but awkward and uncomfortable. Other positions are also possible, but having handgrips attached near the toilet would facilitate things.
jens:
Please tell me you are referring to bending from the waist, and not the … er… member.
It has always been my contention that every house should include a urinal. Much more practical. Not to mention ridding ourselves of the male vs. female toilet seat struggle.