The odd thing about going nude is that it takes practice. I live alone so I can be nude as much as I like but I found that it doesn’t come naturally.
I masturbate a lot, usually several times a day, and I like to get naked when I do it. But I noticed that after I’d cummed, I’d usually want to get dressed again.
Now part of the pleasure of masturbating is feeling the desire to do it build up inside me and then giving in to it and taking my clothes off. But I also liked the idea of spending non-masturbation time nude just doing the usual stuff around the house or garden.
It wasn’t exhibitionism as such ; I didn’t want to be seen or caught by anyone although that’s nice to fantasise about. I just wanted to do some nudity.
At first, I started forcing myself to remain naked for longer and longer periods after masturbating. Then I had the idea of separating my nudity from my masturbation.
I set myself the task of staying nude for a couple of hours after getting up in the morning or spending sometime naked in the afternoon but without touching myself. There was a pleasurable spin off to this. As soon as I did put some clothes on, I’d have an irresistible urge to masturbate and would get them off again to do it.
I quickly began to become more comfortable being naked and the periods of nudity got longer, first all morning then morning and afternoon. If I did have to go out, I stopped putting on underwear so that I felt nuder under my clothes.
Finally, I was able to spend all of last weekend totally nude and feeling completely at ease. I masturbated seven times on Saturday and five times on Sunday and had no urge to dress after cumming.

That is so nice that you are loving your nudity. it is so fun to let your cock hang out.

When I lived on my own, more often than not, if I was home and not expecting anyone, I was nude. When my (now) wife came along, she knew I hung out around the apartment nude, and didn't mind. Out of deference to her, though, since she didn't go nude like that, I didn't do it as often. Now, we're in a situation that's not conducive to such casual nudity very much...we've got a kid and there's also my wife's aunt who lives with us. I am still able, occasionally, to just go about my day naked, and my wife will even sometimes arrange time for me to do so. But, it's much more rare.

I never really needed to "train" myself, though. Although I do understand your concept that, under certain circumstances, once the cum has flown, the urge to dress can hit.

I've often thought I'd love to home office and strip off before I start working. Working in the nude seems kind of exciting and naughty and I'm not about to do it in the office...