Hey, Mark.
Your question is still a bit hazy. Try rephrasing it again. Please be patient with us.
I don't think the longer flaccid necessarily has more blood in it. There are other tissues involved here as well. And it's mainly skin that has been stretched as well to create this longer flaccid.
I think the main reason that after a lot of P.E. your flaccid hang remains for a longer period of time is simply that your dick is not turtling like it does with the shower. My dick, which hangs flaccid nowadays between 6" and 8.5", just doesn't turtle as often as it used to. When it does, it goes back to its old length--3 to 4 inches, but the girth is a lot bigger now.
Don't you think turtling as more to do with those interior muscles that pull it in? When you're cold or stressed don't those muscles go into action to pull it in along with your balls to keep them at the right temp. for reproductive purposes?