Bro if you've ever experienced what a 4-hour erection feels like then you would know what i'm talking about... I've been into Penis Enlargement for years now and the feling i got after a 4-hour erection is on par with the most intense workout i've ever had. If you've ever read some of my past threads on my routines, they aren't newbie workouts. I speak from experience...
Fact is that the tissues in the CC are very expandable and are capable of expanding way beyond what you normally see, it is the tunica that contains and limits the CC's ability to expand. Our Penis Enlargement routines force the tunica to expand beyond what it is normally capable of... that is how we experience 99% of our girth gains. This is true regardless of how conditioned one's penis is...
We may not know the exact mechanisms of how megalophallus occurs, but we can see what actions cause it and can even reproduce it. In fact, we as a community prove it everyday by making gains in girth by forcing our penis' to expand beyond what it once did. Priapism just takes what we do to an extreme. That is more than just theory... and to be honest, the exact mechanism is irrevelent as long as we can reproduce it.