(NSFW) - In a gay relationship wit a sub, not naturally a dom myself, advice needed? (TL;DR at bottom)

Hi all,To quickly summarise I'm a 23 year old gay male currently in a very strong, long distance relationship of around 3 months with a 20 year old male.What with ours being long distance we've naturally had to adapt to not being able to be physically with each other, and so we've found other ways of keeping things exciting, I'm sure you already know what I'm on about so I won't go into details. As a result, in the last few weeks I've found out more and more about what makes him happy and what his 'kinks' are, and it's become vividly apparent that he's very much a submissive. He's openly admitted this, and has gone on to explain some of the more, let's say, extreme things that he likes and would like me to do in the future.Now herein lies my dilemma. I am not naturally a dominant character. I'm confident, don't get me wrong, but the thought of actively degrading the one I love and causing them possible pain is something that has never even crossed my mind before. I'm open to the idea, as with many things I'm willing to try almost anything at least once, plus if he truly likes it then of course I want to do all I can to please him in that way. However what with myself not being naturally dominant I'm looking to any of you who perhaps has experience with this to offer me some advice?For now I've grown somewhat comfortable being dominant via text and voice chat, but I know for a fact if we were to meet tomorrow I wouldn't be able to be physically dominant, not yet.If anyone has any genuine advice I would be more than grateful. Even if anyone can simply offer an explanation as to why he likes being submissive? I kind of understand why being submissive might be a turn on for some people, but I'd be lying if I said I knew exactly why, so a thorough explanation from someone who truly gets it would be appreciated? Plus if anyone has any tips on how I can personally grow more comfortable with the idea, then that would also be hugely beneficial?TL;DR: In a relationship with a submissive, not naturally dominant, don't fully understand why it's a turn on, but I'm open to the idea. Need advice on how to be more comfortable with the idea of degrading/hurting/dominating the one I love.