Such an amazing experience!
My boyfriend and I indulged in a couples float. I highly recommend doing this in complete darkness. The feeling would be best described as floating in the womb; you're warm, weightless and once you allow yourself to really loosen up and relax to the max, it's like being in a meditative state.
Post float you feel like Jello; super chilled out, and less achy.
If you haven't done this, do it. You don't know what you're missing.