You just plop it on a chair, plug it in, and prepare to feel blissed out. (TBH, no one's stopping you from laying it flat on a bed as well! You're welcome.)
There are several Homedics massage cushions on the market with varied features and at different price points, but I love this model specifically because it pretty much has it all: First off, it offers three massage styles to choose from — "kneading" (for a deeper, shiatsu-style massage), "rolling" (for a gentler, up-and-down massage), and the option for an additional "tap" (basically a strong, fast tapping effect for a more ~invigorating~ massage). In addition to an allover massage, you also have the ability to direct the massage on just your upper or lower back, if you're looking to target specific knotty areas. You can adjust the width of the massage action, and there's a "spot" option as well if you'd like to focus the kneading on one area.
Oh, and see that button on the remote that says "heat"? The whole dang cushion heats up too. Yeah, that's right: Once you buy this you can have a HEATED MASSAGE every night of your life! (Have I convinced you to hibernate all winter with this thing yet?)
I have mine on my desk chair at home, and while of course I love putting my feet up, turning on some music, lighting a sweet-ass candle, and plugging the cushion in and letting it do its thing while I sit back and chill TF out, I just as equally enjoy using it while I do some work on my laptop or get in some reading. Just like the intensity of the massage, the level of relaxation you wish to indulge in is your choice alone!
At just under $200, sure, it's not exactly cheap — but considering the price of an average massage, and the fact that you don't need to leave your home, get dressed (!), or put a time limit on your blissful experience...it's well worth the splurge if you intend on using this puppy semi-regularly.