You are blessed with a protective, highly-innervated, erogenous foreskin. Many unforeskinned guys would envy your foreskin. You display great wisdom in wanting to avoid circumcision,
You should thank your parents for protecting your physical integrity. Because of your physical integrity you will be able to have sex the way nature intended it.
Almost all boys are born with a foreskin that does not retract. This is normal. It takes years for the ability to retract to develop. About ½ of boys have a retractable foreskin by 10.4 years of age. Many adolescents still have foreskins that have tips that are too narrow to pass back over the penis head. These foreskins may be gently stretched over a period of time to cause them to widen.
Foreskin retraction is not absolutely necessary. A male may masturbate, have sexual intercourse, and father children with a non-retractile foreskin. Some believe that sex is better with a non-retractile foreskin.
It is normal for teens to have a foreskin that does not retract. One’s foreskin is still developing. If you want your foreskin to retract (not everyone wants a retractable foreskin), then you can help it develop ability to retract by stretching it.
You don't have phimosis because your foreskin will retract some of the time. It is NOT necessary to retract your foreskin when you masturbate.
If you choose to stretch your foreskin, then the goal is to have a foreskin that glides smoothly back and forth so as to provide maximum pleasure.
When your penis is erect, gently pull your foreskin back against the head of the penis. As the head attempts to pass through the foreskin it will stretch the skin a little. Do this several times every day and in a few weeks or months your foreskin will widen and you will be able to retract your foreskin. Do NOT force retraction. Do NOT cause yourself pain.
It works by tissue expansion. Stretching skin induces “mitosis” which is a word that means “division of cells”. New skin cells are formed and the skin expands but it takes some time. The increase in size is permanent. Be patient and give mitosis time to work.
The important thing is to put the skin under tension every day so that it will grow wider.
Search the Internet for:
“How to Fix Phimosis and Tight Foreskins, Solutions That Work”
and you will find the information and support you need.