Darkfur is right about retracting infant foreskins. That can cause terrible damage. The foreskin is fused to the glans like a fingernail to a finger in about 99% of infant boys. Doctors separate it from the glans with forceps before performing infant circumcision. At this stage there is no cavity for germs to collect in so there is no need to retract for washing until the foreskin naturally separates from the glans.
You should have been told to retract when you were a boy, though but the foreskin becomes retractable at differing ages so it can be hard for a parent to know when to raise the subject. It is likely that your mother was not aware that this subject needed to be raised with you. If your father was cut he may not have known either. The good news is that it is not too late.
Here is the link to my detailed stretching instructions. They are on an old board that is now hidden from easy viewing but the link still works.
To copy and paste it highlight the address and press "Ctrl" and "c". Then delete the address in the web browser's Address window and with the cursor still in that window press "Ctrl" and "v". Then press the "Enter" key.
Thatís on a PC. There must be similar shortcuts on a Mac but I donít know them.
Have a read and get back with any questions. The post also covers some related problems like the over sensitivity you describe when you attempted to retract.
Good luck and I hope this helps,