Im 21,man. when my penis is completely hard, the penis head is still covered inside the foreskin. is it a problem? ive never seen my complete penis head out of foreskin. will i able to have sex with my penis (with penis head covered by foreskin) ?

This condition is called phimosis. You should be able to have normal sex . Sometimes the skin becomes looser and moves back after regular sex. If not or if causing pain then a circumcision is advised. I think you might do well

The condition is called phimosis and by itself is often not a problem. Sometimes gently tugging the foreskin back and applying a steroid cream to the exposed glans can help release it over time. If you have pain with sex, urination or develop discharge a minor incision can help open the foreskin & make it looser. Full circumcision is rarely needed unless there is scarring from infection.

Agree with Drs. F and T. Do not force the foreskin back. It will not interfere with sex, but may interfere with hygiene. It would be prudent to see a doctor to ascertain if surgical treatment is indicated. Get HPV vaccine. Wish you good health!