Not sure why, but it helps with the curving-back-towards-the-body bit.
Try just rubbing the base of the shaft, with fingers along the top of the shaft; you can rub the glans, but only the top side. See if you can’t get the popping out that I’m talking about… I’ll try give a better description when I’m not so tired.
The length expansion I think is dependent on rubbing the top side, though I can’t give a good reason why.
Going for 6 inches of girth, wish me luck.