I'm 18 and have never really been able to retract my foreskin.
Differently to a lot of other posts I read, I am not able to retract it whilst flaccid. I'm not sure if this makes a difference.
I have successfully retracted my foreskin approximately 2-3 times in total, however whenever I've done it, the skin has kindd of rolled over into itself and gotten stuck underneath the head. I have been able to manipulate it to free it and didnt even realise there was such a thing as paraphimosis.
In the past I have been sexually active but have only really been able to successfully have sex with a condom as it allows for minimal foreskin movement. Whenever I have tried without a condom, it has just been too uncomofrtable as the foreskin 'rolls' down and bunches up. I do have quite a long foreskin and it seems as if theres more skin that can really go anywhere which is why it gets stuck.
I realise that the fact that I've successfully retracted it in the past should mean that it gets better and easier, however it seems as if each time I do retract it it just tightens back up again, recently its seemed tighter than ever. I can only ever really retract it when the glans is heavily lubricated. I also can't keep the skin stretched for very long when it does successfully retract, as its just too uncomfortable with the over-sensitivity of the glans and the skin bunched up the way it is.
Any tips for getting the skin to stretch properly and not roll up, and also tips for stopping it from re-tightening?

At least that's what some say. In reality, you have just the right amount of foreskin. What you don't have is a loose enough opening to allow full retraction with ease. There's a little ring inside at the end, and that is what needs to be stretched. You may also have to stretch that little web of skin under the pee hole where your foreskin is attached to the penile shaft.

Can you get two fingers inside the opening? If so, you already have a head start. Right now, go back and read several threads of the posts. In one of them, you'll find a link to a page with a drawing of a guy stretching his foreskin. There are also some directions. Try doing it and get back with us on what happened.

Some guy's foreskin bunch up. It's just the way it works a lot of times. Lengthening the frenulum will help to get it back further.

The sensitivty issue is normal. In time, it'll be less noticeable.

1} Cannot retract at all, even when flaccid. May not even be able to see the tip of the glans and urethral meatus at all.

2} Can retract - with difficulty - when flaccid, but not a hope when erect.

3} Can just retract when erect, but the foreskin gets "caught" behind the glans (in that little "groove" called the "sulcus") and is too uncomfortable for sexual activity in the main.

4} Can retract easily over an erection, completely comfortable. "Extras" are that the foreskin moves back and forth over the glans easily, and possibly even retracts by itself on erection.

So the situations described here are commonly and perhaps evenly distributed over these first three descriptions. You have put
yourself in the second - but only just.

Clearly, on average at least, the earlier the classification, the longer it will take to achieve number four, and perhaps the more you might wish to speed up the process by using a stretching device and/ or the betamethasone ointment.

Paraphimosis only has meaning if you do something really foolish - which is to say, leave your foreskin retracted when it is already too tight. This is entirely under your control, so it is not going to happen unless you choose to permit it - such as be choosing to get drunk, as is often the cause. Otherwise, you just pull it forward again.

"Too much foreskin" is an absurdity - like saying your tongue is too long or your arms are too long.

Discomfort when not using a condom is due to lack of lubrication; which indicates nothing less than poor sexual technique (failing to understand the need - or how - to have the young lady fully "wet" before penetration).

To remedy the tight foreskin - you need to do the exercises we describe here (including that for the frænulum), not just retract your foreskin. You need to keep stretching until you are ever so slightly looser than you need, so that the tendency of the skin to "spring" back - which is as it should be - is allowed for.

Sensitivity is not an issue (except of course, as you correctly describe it will be too sensitive if your foreskin is too tight) - you really need to understand the importance of lubrication.