This may or may not help but, after I shortened my foreksin, it kept retracting often in underwear. So wore tighter fitting underwewar and placed dick down to keep skin over glans. And I mastrubated plenty, About 10-15 years later, I noticed the skin had loosened considerably when I foiudn myself spraying when pissing ( when semi cut, there is no need to retract to piss so I had lost that instinct,
When semi cut, masturbation involved tugging skin down tight (which stretches it) and streching skin up too it stops moving. My guess is that this is likely what over the years caused it to lenghten.
In hindsight I had underestmnated how cut I had been, so the tugging when masturbating may not be a thing if you are uncut with much more skin. But it does show that regular "exercise" does strecth it over time. You could just get hard and pull skin back tight on shaft and keep it that way for 5 minutes each day. And frequently pull on whatever overhang you have when soft