Another nice camouflaging trick for those who might have to worry about vanilla friends and family in their homes and do not have a large/private/secure dungeon or play area:

My wife had a smallish tapestry that she had been wanting to put up, so that made an excellent excuse to mount some solid eyebolts to the wall and mount some hooks to the back of the tapestry. It's a lovely bit of wall decoration, and can be easily taken down to provide nicely anchored bolts for...well, you know.

Between wall tapestries like this, some well placed hanging plants, and a nice solid coffee table/end table a very innocuous looking room can be converted to a nice dungeon space with a relative minimum of fuss