I used to. I could get about halfway down the shaft with my lips. I've nutted in my mouth a few times. I've even let my wife see me do it. She didn't believe me but when I showed her she helped Jack a load into my mouth and it got her off too.
A very long time ago my wife tried to put my own dick in my mouth.
I'm a sports man but this flexibility I hadn't.
So she then jerked me off to eat my own cum.