This seems like a major troll post, but since OP is supposedly my Prairie brother, I'm going to treat it as a genuine question.
On Penis Size
Unlike respondent-dependent questionnaires, we actually have fairly good data on penis size averages. This information is really only useful to determine if you fall within a "normal" range, as there will always be severe outliers.
The probable best study on the matter was published in the British Journal of Urology. It was a meta-study examining the results of tests done on over 16,000 men. In all cases, the measurements were made in a clinical setting by health care professionals. And... they came up with an average length of 5 point something inches (erect) and just under 5 inches in girth. So, it sounds like OP is doing just fine.
On "Enhancement" Surgery
There have been surgeries of this type for years. Length enhancement has usually involved severing the suspensory ligament. Results varied and, trust me, you really don't want to do this.
Girth enhancements are even worse. Most involve injections. HLA injections are the safest but they are temporary and you cannot get huge gains. Fat transfer injections (once the gold standard) often leave a lumpy texture to the entire shaft. The more "exotic" injections like collagen and various polymers are straight-up dangerous and often only available through medical tourism.
The new type of enhancement you are either looking in to or shilling is a polymer sheet that is inserted under the skin, around the corpora cavernosa. This procedure is somewhat akin to the old enhancement surgery in which a flap transfer of fat (usually from the back of the leg) was wrapped around the penis. The only difference is your body is not going to absorb the polymer sheet.
But, now, the bad news... Your body can certainly reject a polymer implant. In fact, it happens all the time. Dr. James Elist in California has been putting these implants in for a while now. Anyone interested can google the "bad" results of the surgery.
As a side note, because someone mentioned it - Yes, you can have testicular enhancement. One, you can have a complete replacement enhancement. I don't know why you would willingly castrate yourself, but I guess if you had testicular cancer, it makes sense. FYI, the "neuticals" they put in were originally developed for show dogs. Two, you can have encapsulation enhancement. That is where they put a hollow shell around your testicle. The down side is it makes you functionally infertile (and it can lead to bad and painful side effects like hydrocele and testicular torsion).
A final thought on enhancements. Your penis is not your kidneys. You only have one (well, most guys only have one, but that's another story). If you do something to fuck it up, you are impotent - probably for life. And you are going to do this why? To impress some random pump and dump? Again, why?
On Girls and Penis Size
Out of the thousands of girls that I have interviewed about sex over the years, do you want to know how many brought up penis size? Very few.
Girls care up to a point. Younger girls seem to care more than older ones. And the previous posters are correct on several points. Women can't eyeball measure for shit. They often have no idea. And your size will depend on the girl's feelings towards you. Some asshole that's annoying them is packing a gherkin. That jock that alpha widowed them has a Hillshire Farm Summer Sausage in his pants.
This is only a concern in a specific circumstance, as far as I can see it.
Do you care if a random slut likes your size? You shouldn't, she's a pump and dump.
Do you care about other guys? If you do, you are probably on the wrong forum.
So, you should really only care about it in the context of an LTR. And, even then, only if she brings it up. If she says she is unsatisfied (very unlikely to happen), there can only be a few reasons. She is trying to get you to dump her. Or, she is a (former) carousel rider who truly has had and enjoyed some monster cocks. Or, she was one of those "lucky girls" who happened upon Mr. John Holmes in the guy(s) she previous slept with. Or, she is some sort of weird primordial size queen. If any of those concerns come up, I would leave the girl long before I let some doctor take a whack at my junk.
In Closing
If you are really concerned with "enhancement", get a low-traction stretching device and, maybe, a low-pressure water pump. All together that would cost you less than $500 and it actually has research to back it up. You won't become a porn star over night, but you might add an inch or two over a few years.
Did I put way too much thought in to this response? Yes. Yes, I did. This is what happens when academics retire.
On Penis Size
Unlike respondent-dependent questionnaires, we actually have fairly good data on penis size averages. This information is really only useful to determine if you fall within a "normal" range, as there will always be severe outliers.
The probable best study on the matter was published in the British Journal of Urology. It was a meta-study examining the results of tests done on over 16,000 men. In all cases, the measurements were made in a clinical setting by health care professionals. And... they came up with an average length of 5 point something inches (erect) and just under 5 inches in girth. So, it sounds like OP is doing just fine.
On "Enhancement" Surgery
There have been surgeries of this type for years. Length enhancement has usually involved severing the suspensory ligament. Results varied and, trust me, you really don't want to do this.
Girth enhancements are even worse. Most involve injections. HLA injections are the safest but they are temporary and you cannot get huge gains. Fat transfer injections (once the gold standard) often leave a lumpy texture to the entire shaft. The more "exotic" injections like collagen and various polymers are straight-up dangerous and often only available through medical tourism.
The new type of enhancement you are either looking in to or shilling is a polymer sheet that is inserted under the skin, around the corpora cavernosa. This procedure is somewhat akin to the old enhancement surgery in which a flap transfer of fat (usually from the back of the leg) was wrapped around the penis. The only difference is your body is not going to absorb the polymer sheet.
But, now, the bad news... Your body can certainly reject a polymer implant. In fact, it happens all the time. Dr. James Elist in California has been putting these implants in for a while now. Anyone interested can google the "bad" results of the surgery.
As a side note, because someone mentioned it - Yes, you can have testicular enhancement. One, you can have a complete replacement enhancement. I don't know why you would willingly castrate yourself, but I guess if you had testicular cancer, it makes sense. FYI, the "neuticals" they put in were originally developed for show dogs. Two, you can have encapsulation enhancement. That is where they put a hollow shell around your testicle. The down side is it makes you functionally infertile (and it can lead to bad and painful side effects like hydrocele and testicular torsion).
A final thought on enhancements. Your penis is not your kidneys. You only have one (well, most guys only have one, but that's another story). If you do something to fuck it up, you are impotent - probably for life. And you are going to do this why? To impress some random pump and dump? Again, why?
On Girls and Penis Size
Out of the thousands of girls that I have interviewed about sex over the years, do you want to know how many brought up penis size? Very few.
Girls care up to a point. Younger girls seem to care more than older ones. And the previous posters are correct on several points. Women can't eyeball measure for shit. They often have no idea. And your size will depend on the girl's feelings towards you. Some asshole that's annoying them is packing a gherkin. That jock that alpha widowed them has a Hillshire Farm Summer Sausage in his pants.
This is only a concern in a specific circumstance, as far as I can see it.
Do you care if a random slut likes your size? You shouldn't, she's a pump and dump.
Do you care about other guys? If you do, you are probably on the wrong forum.
So, you should really only care about it in the context of an LTR. And, even then, only if she brings it up. If she says she is unsatisfied (very unlikely to happen), there can only be a few reasons. She is trying to get you to dump her. Or, she is a (former) carousel rider who truly has had and enjoyed some monster cocks. Or, she was one of those "lucky girls" who happened upon Mr. John Holmes in the guy(s) she previous slept with. Or, she is some sort of weird primordial size queen. If any of those concerns come up, I would leave the girl long before I let some doctor take a whack at my junk.
In Closing
If you are really concerned with "enhancement", get a low-traction stretching device and, maybe, a low-pressure water pump. All together that would cost you less than $500 and it actually has research to back it up. You won't become a porn star over night, but you might add an inch or two over a few years.
Did I put way too much thought in to this response? Yes. Yes, I did. This is what happens when academics retire.
Currently out of office.