It takes some getting used to as you start out in SL. I've been doing both in SL for a couple of years and for almost 18 years RL. Some of the big differences are its harder to form the "real" connection with someone that you get in RL (though just as rewarding when you do). I have several pets I consider myself especially close to, as well as friends. I run a large station dedicated to erotic hypnosis, D/s, and fetish fun, a small club, a store where I sell some of the scripts I've written for auto-trance machines in game, and my own hypnosis group. out of all that I consider maybe 1/5th the people I "know" as close friends or pets. Those who are MINE know who they are so I'm not going to list names.
One thing you have to remember - and it can be hard - is that though it's pixels on a computer screen, its also a real person behind those pixels on the other end. A person with real feelings, real likes and dislikes, and with their own level of emotional investment (or lack thereof) in the game and in the friendships and relationships there. So you have to balance fun with safety, as while you can't PHYSICALLY harm someone with a slip like you could if you flogged them incorrectly in RL, in some cases you CAN cause them real emotional distress, especially if they are highly invested in the game emotionally due to real life limitations.
With that said you can also have a LOT of fun there too, both in terms of D/s, and hypno play. SOME Of WHICH you probably couldn't, or atleast shouldn't, do RL and others of which your lifestyle may not allow in RL without riskig career or societal repercussions if discovered. For example indulging in taboo's that are more extreme such as beastiailty, necrophillia, body transformations into furrys, walking around "towns" nude and leashed (as long as the town is in a adult sim). You can indulge in virtually anything you can imagine, so it is a fertile playground for the mind. even in non BDSM or hypno play there are so many options, being Jedi or sith, vampire, werewolf, demon, furry, robot, android, gynoid, etc. So the gae truly does offer something for almost anyone.
As a venue for D/s and hypno play there are unique opportunities, restrictions, and challenges. I'll go into those in more detail in another post. but the opportunites can be very entertaining.