I just
explained the situation, above.
If you want to have your foreskin move freely forward and back where it does not now, then it occurs to me that you need to stretch
both your foreskin opening and your frænulum. On deeper consideration, it occurs to me that it is perhaps your frænulum itself that is pulling the foreskin back when you have an erection
and causing it to then "bunch" behind the glans. But it is a
minor degree of tightness to the foreskin
opening - and the shape of the "corona"; the rearmost part of the glans - that causes it not to come forward again easily when you lose the erection.
Now there are no "other methods" that we need to explain to "see if my foreskin will glide back and forth easily". The stretching methods are all
thoroughly explained here in
other discussions, all you need to do is to read (many of) those discussions and learn what is involved. The frænulum stretching is in fact slow and tedious and will thus take quite a while longer, but also is very
practical to do as you do not even need to take your penis out of your pants, so you can do it in all sorts of places. (Since once you have a grip on it, no movement is involved, no-one is particularly likely to imagine you
are masturbating if they happen to drop in unexpectedly.

)
It's good that you have read elsewhere of the "gliding action" concept. Trouble is, you have no doubt
also read a lot of complete nonsense into the bargain along the way - you
do have to be careful "researching" this topic anywhere on the Internet - or elsewhere (wherever that might be). While the "gliding action"
is beneficial for sexual function (of all sorts), and
is a clear advantage of having a foreskin, it is probably not particularly important most of the time but rather where things are not working out too well - it is more a "fall-back" advantage of sorts, and I do not think you should be putting too much importance on it.
Curious that you refer to circumcision. The "reason why you have stayed intact" is nothing more than that there simply is
no advantage whatsoever of circumcision. It's really not a consideration. If you ever
thought there was some advantage, then you would implicitly have been ignorant in some way or another, of how sex really works.