If you go online to this photo: http://www.urologicalcare.com/img/Mechanism-Erections.png
you see a cross-section of a penis. You can see that the "corpus cavernosum" fills up with blood when erect, but the bottom tube doesn't fill up as much...so it doesn't get hard like the top two side-by-side tubes. Maybe that's why the top feels harder than the bottom. If it's a bigger problem than that, then you should put it on your "To Be Discussed" list for your annual doctor visit.
If you think this is an issue that your concerned about then have your doctor check you out to make sure all is ok. Its always good to see your doctor once a year anyway and this might be a good reason. Catching things early is always good. I had my psa tested and was high and they did a biopsey on my prostate and found cancer. They caught it early and im ok now. just a point of reference to always see your doctor when you have concerns.
Hi,
It's not excessive skin. It's normal tissue. The penis is hard everywhere else, apart from the head (obviously) and under the penis. Like unflexed muscle.
Hi and welcome. Sounds normal, sounds like excess skin.