"Big" is mostly a matter of self-deception.
Although there have been quite a few pictures here of male members that truly were freaks of nature, better suited for a side-show than a bedroom, most of us are AVERAGE -- that's the quintessential meaning of the word, and the measure of the word is 6 to 7 inches.
But most males come up with some truly insane and inaccurate ways to measure their cocks.
Here's some facts and some guidelines for measuring.
Males always say things like "my dick is xx inches long" and that's just as true as "I can eat pussy all night long." Give it a FUCKING REST!! The ONLY valid way to measure your dick length is to take an old-fashioned wooden school ruler, place it flat on TOP of your dick, and push it into your pelvis as far as you can, or until you draw blood. Looking down from above, where your dick ends is how long your dick is.
Read it and weep. It does not get any longer than that. If you know what parallax error is, then you know that this actually makes your dick measure a quarter inch longer than it really is.
Now -- you uncut bastards, you're a special case. Your prepuce DOES NOT COUNT for your dick length. If you're really ignorant, "prepuce" is your foreskin, the male anatomical part most commonly regarded as the most repugnant, rejectable, and disposable part of a man. Besides his personality.
Do NOT measure your prepuce as being part of your dick length. When you have your dick inside your fuck partner, your prepuce always slides back, so the only length they can feel is from your urethral opening and back. You are a DICK, and not a fin fish as defined in the Texas Parks and Wildlife Fishing and Hunting Regulations. Pinching a fin-fish's tail to make it long enough to keep is not the same as pinching your prepuce to make your dick long enough to fuck.
You are just a dick, not a game fish, no matter how large your bag limit or how willingly you'd eat a dick like you would eat a game fish. So skin it before you measure it.
For length, use the school ruler method. If you are actually longer than a 12-inch ruler, I pity you but you should either say "12 inches plus" or else get a goddamn yardstick from the sewing store.
Using a carpenter's tape measure does NOT count. If it did, I could hook the end of the tape in my asshole and measure a 12-inch dick right now, and I don't even have an erection. So could you. A few of you are doing exactly that, as you read this.
Girth is a technical term that means "how big around it is." I know I've been using a lot of technical terms here. Get over it. Get a dictionary. And NO, that is NOT a book that tells you how large your penis is, except that a few of you have your pictures next to the words "inflated" "exaggerated" "mendacity" and "fraud." And -- I left out "laughable" and "miniscule."
The only accurate way to measure the girth of your dick is with a flexible tape measure, the kind you can get at the sewing store -- or can borrow from your gay clothing designer best friend. You measure your girth by wrapping the tape measure around the AVERAGE-SIZE part of the shaft of your cock. And you cannot measure the "width" of your dick, because dicks are oval-shaped in cross-section and not all proportionately equal in width by depth. Girth counts. Only. And please don't say that your dick girth is how WIDE it is, because if your dick were that wide it would not be your penis, it would be the tail of a goddamn beaver.
And when you measure girth, wrap the tape just one time, bitches. One time. If you're one of those mushroom-headed fuckers, do NOT say your dick girth is the circumference of your mushroom head. That's a fucking lie, and you know it. If there's an inch difference between your mushroom head and its supporting structure, and if you think it matters, report both numbers separately. I've been told that some dick recipients like a big-ass dick head and a slender shaft to push it in and out. in this case, accurate reporting will get you more ass that actually wants YOUR individual dick.
Ot 500 more just like it.
To give you an idea of what's "average," six inches length is considered "average." A majority of women find that to be perfect, as long as the dick owner has a clue of what he's doing. If he does not know, then dick length is totally irrelevant, because he's a lousy fuck, no matter what. As far as men preferring larger, average, or smaller? I don't know about THAT, but I do know that pussies can stretch a lot more than rectums, so at least in theory, a pussy can fit a huge dick better than a rectum can fit a huge dick. Your ass-pounding mileage may vary.
If you are shorter than average, you may have to work on having a nice personality and good sexual techniques. Do that, and you'll be getting more ass than a ride at Six Flags. if you are longer than average? Same thing. The ONLY person who gives a shit about your freak-of-nature footlong schlong is YOU. Be a nice person and a good lover, or get used to jacking off. Jacking off ALL THE TIME.
As far as girth, I won't speak to "average" except to note that "average" girth is proportional to length. The rest of you fuckers can work the numbers. I am not in the business of measuring thousands of dicks to determine "average" girth, or "average" girth vs. length.
But here are a couple of numbers to make you shut your mouth.
A standard 12 oz beer can (Miller, Bud, NOT Coors) is approximately 8 inches in girth. So if you claim a "beer can dick" you better be close to this. Also remember that a standard 12 oz beer can is only 4 3/4 inches tall / long. That means that your "beer can" dick is nearly 20% shorter than average, and too fat to use. Don't believe me? In the privacy of your own home, try wrapping your lips around a beer can.
Next measure -- a paper towel roll. A paper towel roll -- exact same size as a toilet paper roll -- is just shy of 5 1/2 inches in girth. Again, in the privacy of your own home, maybe the next time you're sitting on the toilet jacking off (that may be right now for some of you), see if you can put your dick inside the toilet paper roll. If you can, then your dick girth is LESS than 5 1/2 inches.
I won't offer any smaller standards for dick girth comparison, because some of you might get your feelings hurt.
I will finish with this -- do NOT use a peter pump when you measure, unless you use the same peter pump every time you show your erection to another person. THAT should be a much greater embarrassment to you than knowing your dick isn't as big around as a beer can and you don't need a yardstick to see how long it is.
Now all you mutherfuckers need to QUIT LYING and MEASURE UP to the truth. If you really do have an actually huge dick, that's your business. If you are AVERAGE, that's your business. If you have a truly small cock, that's your business.
Well, your business, and the business of all the people who want to fuck you. And there are enough people in the world who want different sizes of dicks that you will have NO trouble getting ass, just as soon as you quit being a DICK and lying about your peter.