I was started masterbate with plastic bags before three years ago.i used hair oil inside the polythene bag ,then insert the penis and rub with bed. my masturbation timing was 10 mnt to 30 mnt, but suddenly i feel little eaching on left side foreskin?

It sounds most likely here that you are having some irritation from either the friction of the masturbation, or a reaction to the lubricant inside the plastic bag. It is likely that if you stop this practice for a few days, the irritation will get better. See your doctor if it does not. Good luck.

You might have irritated the area in the process you describe . Try some other way-if you want to masturbate.. Keep foreskin clean with soap and water