At what age did you learn to retract the foreskin?

It was around 5 or 6 years old.

I don't remember exactly who I learned it from first. It was either the pediatrician or my grandmother.

@mediguy183 I too had a part of the inner foreskin which was still fused to the glans corona aged about 11 or 12, about 2mm right in the dorsal side, so when I looked down at my erect penis, foreskin back, it was there, right in the middle of the corona.

When prior to masturbating sitting on the toilet just back from school, I pulled my foreskin back hard, then with my thumb exerted some pressure against it, and I forced it to snap away, leaving that bare part of the corona very sore and sensitive.

Strangely enough, the pain on the corona which lasted a day or so, gave me a virtual constant erection.

My glans was now fully free of the fused inner foreskin which had been forced away over time by the girl along from me.

This little fused part seemed very stubborn, but at least my glans was free, and looked like the flared red mushroom it became.