Hello, If you are able to retract your foreskin in flaccid state of penis then it should not be a big problem for you.it is  not necessary to pull it down over the head when erect. But if you can t pull your foreskin even in flaccid state then,you would be needing a circumcision. If the problem is not that acute or if you want to avoid circumcision,you may try using some methods like stretching or application of steroid creams For stretching...  Use baby oil, Nivea or vaseline as  a lubricant.apply on the foreskin inside and outside and pull  the foreskin forward away from the body several times then pull it back as far as it will go onto the glans (head of the penis} and hold it in this stretched position for several minutes. If done with an erection the stretching will be even more effective. Do this several times a day. Specially do it in morning after bath. Steroid creams can be used... Steroid creams should be used next if no significant progress has been made after a month. The cream you need is called Betamethasone 0.05% .The cream should be massaged into the tight part of the foreskin inside and outside 2-3 times a day for at least a month combined with further stretching.  If these methods fail ,then better would be to go for circumcision. Thanks