Obviously, you’ve never been fishing, Scratch.
Men measure their penises so that they can more efficiently lie about the size.
Ask any angler how big the last fish they cought was, and you’ll likely find that they add at least %10 to the truth.
The same may well hold true.
I didn’t know men HAD to know this? Do other guys go around saying, “Hey, Dude, what size is your dick?” Or do you have to have the size tattooed on the inside of your palm so other guys know to be intimidated or not when you shake hands?
When will people realize that it’s not the SIZE… it’s the FIT!! (use your imagination;))
If someone asks you what size you are, just respond, “Well, my girlfriend calls him “OH GOD!!””
Sorry, oldscratch, I meant to also reply to the OP.
I remember trying to measure mine when I was a kid because of all the juvenile jokes making the rounds among my peers, and I was desperately afraid I wasn’t ‘manly’ enough.
(hey, I was a kid.)
I never got an actual measurement though, 'cause I couldn’t decide where to put the ruler. If I put it underneath I got a different measurement than if I put it on top. And even then it kept shrinking or growing depending on how vigorously I ‘measured’ it. Finally I gave it up as a bad idea and just started lying like everybody else.
I’ve since been assured that it is ‘big enough’. 
simetra, loved the business card!
We all know it’s not the size. It’s the surface area of your dorsal side that really matters!!
Along the top, dude.
Give a guy a tape measure and tell him to measure along the bottom, he won’t start at the base. Nope. He’ll start from the top of his butt-crack. Then he’ll give you some ungodly figure like Simetra’s.
They all do it.
We have to know for when we write to the Penthouse Forum, of course. I mean, you never know when you might run into three beautiful bisexual nymphomaniacs and you might not have a ruler handy… 
Sigh. A lonely night, a few years back, I measured along the bottom but apparently started a little too far back. I thought “Wow! If this is how they measure, then I’m not that bad after all!”
Of course, now I’m going to have to go home and measure along the stop. And check the circumference, too, so I can tell if I should feel inadequate or not.
Every man measures something to determine his self worth.
From his penis to his pay check to his wife’s breast size, you can read about it all here.
IIRC, the “Hung Jury,” which is kind of like MENSA for the penis, says that the penis should be measured from the bottom.
Male1: … just like every guy knows the size of his penis.
Male2: Huh? I don’t know mine.
Male1: Bullshit! Everyone measures it!
[Later that night …]
Male2: What if everyone else measures it? I mean, maybe I’m really the only one who doesn’t. I want to fit in, don’t I? Well …
[Male2 measures his penis, smiles proudly, then flips the ruler over to use the ‘inch’ side instead of the ‘centimeter’ side. He spends the rest of the night telling himself that size really doesn’t matter.]
[The next day …]
Male2: You know, just like every guy knows the size of his penis.
Male3: Huh? I’ve never measured mine.
Male2: Bullshit! Everyone has. Don’t lie.
And so on.
We measure them to keep ourselves humble…
[ponder]did I say that out loud? Shit![/ponder]
[gruff blustering]We measure them to keep other guys humble! Hoo-rah![/gruff blustering]
Scrotum forward might be a good measurement, but the top length is really what counts. The penis can’t be sheathed in anything farther than the pubic bone so why would the rest of the tool matter?
Me? I measure my prick every 15 minutes and log the results in a nifty chart that accounts for temperature, state of arousal, barometric pressure, altitude, wind speed, kilocalorie intake over a 12 hour period, etc.
You might be wondering why I do this. Short answer: the aliens insist.
It has a neck?!? Damn oldscratch!
I can honestly say I’ve never measured my penis. Is it because I’m confident in my manhood, or is it because I’m afraid to find out the truth (or is it because I lack a ruler and don’t want to get kicked out of Office Depot)?
Perhaps you’ll never know.
If it’s 5.5’, being in the next room might not be enough…
I gotta tell you Tymp, you sound like a guy with maybe a little too much time on his hands (bu-dump)
As for the 5.5’ penis, I am reminded of the chapter in Drew Carey’s “Dirty Jokes and Beer” entitled, “101 Big Dick Jokes.” My favorite:
“My dick’s so big it won’t return Spielberg’s calls.”
another
“My dick’s so big the FAA requires hazard lights.”
Getting back to the thread, men measure their dick for the same reason they climb mountains and race cars. It’s there and there’s nothing better to do at the moment.
If you’ll excuse me now, “Big Jim and the Twins” and I have to take care of some errands.
I never really was concerned about the size of mine. Truth be known, the only person who ever asked me what size it was was a woman. I had to go to the bathroom and measure it for her.
[sub]7.5, why?[/sub]
:D:D:D:D:D:D:D:D:D:D:D:D:D
My SO: My penis is too small.
Me: What the hell are you talking about? I think it’s fine, and mine’s the only opinion that matters.
My SO: How long do you think it is?
Me: It’s X inches long. (And no, I’m not using Roman numerals. I’m just not going to post it for everybody’s greedy eyes.)
My SO: No, it’s smaller than that.
Me: No, it isn’t. It’s X inches on the button.
My SO: I don’t think so. It’s too small.
I immediately got up, ran downstairs, got my tape measure out of my knitting bag, trotted back up, and measured it.
X inches, on the button.
She likes me! She really, really, likes me!