1.) actual changes to your appearance will be very very gradual, and somewhat under your control cause you can still dress femme and shave if you want to. Your mood will also naturally crash a bit for the first few weeks of being off so you kinda need to go off for a month or so to really feel what it's gonna feel like.
2.) Jerking off instead every time I thought about taking hormones definitely helped make it permanent, it helped me learn to enjoy the dysphoria more and more, and was generally a lot of fun.
3.) Because it's so gradual you can take a long time to decide whether it's gonna be permanent, but for me, the more changes I got the more I got turned on by the changes and the more I wanted my body to feel manly and felt genuine gender euphoria from detransitioning. Any regret or dysphoria I still feel is a huge turn on, and I think if you're into the idea of detransitioning or have a kink about it it's probably because on some level you do want to enjoy the experience of being male and having a more male body.
4.) Once I had stopped taking HRT for a month or so and had readjusted I realized that I just didn't feel like a woman anymore. I felt like before I had transitioned and I still had doubts about it. Part of me still wishes I could be a woman or be more femme, but mostly realized I feel okay with being a man again and that when I had been femme I had fantasized about being a man too. So I feel some dysphoria and euphoria either way, but as a man my dysphoria from being masculine is a huge turn on. Any sting of regret and dysphoria I get feels good in a way