foreskin behind head but it keeps rolling back over it

I've been pulling my foreskin behind the head recently, I've been gradually pulling it back every day in the shower. Now I can get it behind me head when erect (it takes a bit, but I get it there.) Thing is, my foreskin is kind of building up on the left side of the head (the right side doesn't have that much skin there, so it stays till the left side starts), so it keeps folding back over the head of my penis when I don't want it to. Is there any way to stop this? Should I pull the foreskin back a bit more, like a centimeter or two along the shaft?

Thanks in advance.