How to cure phimosis (a tight foreskin)
How often can I masturbate? Age:17

No more than once every 3 days is my advice.  Ideally you should try to go for 4 or 5 days.  When you do masturbate - remember - as little pressure as possible -  and for as little time as possible.  

Save sexual enjoyment for sex with a real woman,.  The penis wasn’t meant or designed for the strong pressure of the hand.  It was designed for the soft walls of the vagina to gently roll the foreskin back and forth.

Hi I'm using the stretching technique and I have the steroid cream. However I'm confused. If I'm supposed to use the cream while stretching what can I do to get a good grip because it's very slippery. I have both hydrocortisone and betamethasone.

My theory is that a lot of phimosis cases - particularly if you have not got a skin disease - are caused by damage to the penis due to too much pressure applied in masturbation.  So follow my advice on my home page.  Masturbate as little as possible.  No more than once every three days.  That is all you need to do.  This will repair your penis and the spongy chambers should inflate to their proper position.  This will stretch the foreskin.  Plus you should then get more strong long lasting spontaneous erections.  These are erections without touching.  You want these.  You want these to last a long time.  Do not masturbate to prolong the erection though.  They will come once you have rested your penis for sufficient time to have repaired fully.

Regarding your cream.  I would try my advice first.  Then go for the conventional advice of using cream and stretching.

How to cure phimosis (a tight foreskin)

Masturbating in the wrong way is the main cause of phimosis.

See this scientific study that links masturbation to phimosis:

The penis basically consists of 3 spongy balloon-like chambers that fill with blood on erection.
See Diagram:
This page shows the functions and mobility of the foreskin:
This shows how the foreskin is attached to the glans by the frenulum:

Masturbating can be damaging to the penis if you apply too much pressure. It damages the spongy tissue chambers of the penis. Consequently the 3 spongy chambers do not fill out with blood and expand the skin. This leads to a tight foreskin.
A sensitive glans (head) is a sign of damage.
So what you need to do is allow repair to happen. Don’t masturbate as much. And when you do masturbate, don’t do it for a long time.
Too much masturbation (especially with the wrong technique) can also cause micro-tears in the skin, which form scar tissue; scar tissue is less elastic than unscarred tissue.

So, make sure you are not using a damaging masturbation technique. Just lightly grip the penis and move the foreskin up and down.
Once the inside structure starts to repair, the 3 spongy chambers of the penis will inflate to their proper position and this should expand the outside skin and there will be extra ‘give’ when trying to pull the foreskin down. In time, it will then be easier to retract the foreskin over the head.