I’ve never been told not to pull back but I was told in effect that I should be pulling back. When I was 18 I went to stay at an educational academy in Japan for 8 months, all male. One of their rituals was to have a bath every evening. Not the kind of bath we’d recognise, probably 4’ x 4’ x 4’ with no soap allowed. You had to wash next to the bath, remove all suds and then finish by soaking in the bath itself. There was only one for the academy (about 25 males) and it started with the director taking first bath then working down seniority of teachers then pupils. Most went in one by one but towards the end often there would be a few of the stragglers washing at the side with one boy in the bath. Occasionally a older member of staff would come in to check or simply to push in if he’d missed his turn. At first I thought they were all circumcised but after a while I realised they all pulled back as they got undressed. It was pretty much obligatory although no one told me to do it. I think a lot of them saw my covered glans and disapproved. So of course I started pulling back for bath time. The only time I remember a comment was when one of the senior teachers, who must have seen me unretracted before, looked down and said “that’s better”. This was a long time ago so I don’t know if this is still the custom in Japan.