I started semi-frequent sensory deprivation seasons about a year into my current job in Seattle after receiving a free weekend pass to a resort/spa for me and my "girlfriend". Going to the spa is pretty expensive, so I found a place that does only floating and massages. I don't personally enjoy massages, but I would recommend doing the massage first if you get the choice. The float itself is actually pretty cheap, only 50 bucks for an hour, which is incidentally the amount of money I spend per week on periodicals.
The tank itself isn't as intimidating as I thought it would be based on the media portrayals of isolation tanks. I was expecting a bullet shaped, metal coffin. In actuality, the tanks turn out to be cool, futuristic, egg shaped pods. The people who run the join tend to be the really nice cardigan wearing, pseudo-hippie set who have no problems when you accidentally flash them your penis. You'll be given a lot of opportunities to do so; I have no idea why the bathrobes they give have to be so short, but whatever.
The first thing you do is shower, which is why I recommend you do a season in the morning if you can since you'll be taking a shower afterward as well and you shampoo both pre and post. They give you a couple of minutes before you enter if you want to clear your mind or start meditating and I always take the time to stretch out a little bit. You can put in ear plug which I always do and then you get naked and step into the pod, lie down and then they close the lid.
The water is very very salty and probably the perfect temperature for doing anything. There is actually a lot of room in there, you can just about stand up if you short like me, and if you're in the center of the pod you have to swim half a body length to hit the sides. I personally like to float fairly near the wall so that if I ever kinda start to nod off I can just hit the wall to recenter myself. You float in the water in the complete dark with pretty much just your nose and mouth above the water line.
It takes....some amount of time to really start relaxing. I think it only takes 10 minutes. I'm fairly sure it doesn't take more than 30 minutes. You skin takes a little bit of time to get acclimated to the salt in the water. The smell of the salt in the water takes a little bit of time to get used to. However, the biggest thing that you have to get used to in order to relax is getting used to all the fucking noises you body makes. When you get in that tank, the sound of your own breathing is the loudest thing you have ever heard. It's like a goddamn tea kettle when you breath in and a fucking jet taking off when you breath out. And your stomach makes these incredible loud noises for no reason whatsoever. So, you fight your brain for a little bit until you start to tune out the noises you make through your body.
When you relax in there, you relax everything. You relax muscles you don't even know you're tensing. Like, I know I tense my shoulders all the time so they're expected to go limp a little bit. But I had no idea that I flex my thighs ALL THE TIME. And my thumbs? I'm constantly wiggling them around. So, if you're even remotely interested in going, go to find out what utter relaxation feels like. It's just so blissful and soothing that when you get out of the tub it almost hurts a little bit when the muscles you tense all the time spring back. It's not that your body goes numb, it's just that when you completely relax you just don't interact with your body anymore.
So, perfect relaxation is a great reason to try a sensory deprivation season. Whenever you're feel a little bit stressed, like say after 80 hours of work a week or a particularly good therapy season, going is a great way to spend your day. You can go for longer if you feel like, but really an hour in isolation feels the same as a three hour season. I really cannot tell the difference. But the reason I keep going instead of drinking a lot of booze or getting stoned is that during sense dep I can achieve lucid dreaming.
I dream pretty vivid dreams all the time. I twitter about a dream a day, but that's only because I twitter dreams that actually have something to write about instead of just the weird stream of disjointed images and feeling I usually have or the fairly large amount of erotic dreams I experience (my therapist loves talking about those dreams in particular). I sleep very poorly, of which I've talking about a bit, and it's gotten worst since I got dependent and then off sleep aids. My really super awesome dreams are kinda the bonus prize for not being able to sleep more than an hour in a row. And yet even though I have a lot of dreams, lucid dreaming I can only do while in the tank.
It starts off once I've gotten perfectly relaxed. You body feels like it melts aways, your ears stop ringing from trying to hear anything and you nose shuts downs. The only thing that remains is what you can see in that completely dark room. Once you get perfectly relaxed your mind keeps trying to figure out it's environment and those weird moving lights you see when you close your eyes start moving. Eventually I start to see a rainbow like if you're looking through a kaleidoscope but with way smoother transition between colors and shapes. Once I get there, I just need to relax my brain just a little bit more and then I'm there. I can fly through space, I can ride a dinosaur through a field of naked people, I can have whole conversations with myself including playing games like candyland or monopoly. And no matter how weird or now complicated I make my dreams when my season is over I can remember them with perfect and wonderful detail.