If we’re just growing our penises rather than adding to it, then the supporting structures would get noticebly weaker; though I happen to believe we can compensate blood wise.
In images and resizing it’s a general guideline that you can’t increase an image more than 140% without someone noticing. At 140% it begins to become apparent that supporting structures of information is insufficient for the algorithm to output a clear image. That however doesn’t stop someone from resizing it to 200%, but it just expands everything and looks terribly pixelated and splotchy. Oddly enough I think something like this can be applied to the thought of getting bigger and not adding more. Considering that we’re dealing with the “full amount of the image” we also need to deal with “the full amount of the dick” (ie. Volume) rather than just length and girth separately.
In regards to the penis, 140% of 10 cc is 14 cc. If you start off with a larger penis I think there’s reason to suspect that there is more interweave of structure. So a penis that starts out at 15 cc can go right up to 21 cc before the first signs of structure integrity being lost. I don’t see any reason why someone can’t double their penis size though.
When I feel my penis, while it is equally as hard and and feels bigger, it doesn’t feel like there’s “more” penis persay. Just that’s it’s in an expanded state. Though “feelings” aside, I’ve only gone from 10 cc to 13 cc (roughly).