Gravik,
What's your overall health like?
Circulation is a big issue when talking about non-aroused levels of engorgement.
Without getting too far into details nobody really needs to hear anyways, I'll just say that I'm much more likely to turtle up when I have any "digestive" or "elimination" issues.
The cleaner I am the "hangier" I am.
Another thing is tension; any kind of stress, excess caffeine and, somewhat counterintuitively; lack of exercise all lend a hand in creating turtles.
Sometimes there are answers you'd never even consider; take a look at your environment and see what might need a little tweaking.