One nifty toy which has been helpful in relieving stress around our home is the Harmony Roller. The Harmony Roller is simple in concept - it's basically a ball, about three inches across. The ball sits in a little enclosure that holds it in one position while also allowing the ball to roll. The enclosure has a soft, textured grip along the outside, making it fit comfortably in the owner's hand.
With the grip firmly in hand we can roll the ball over a muscle (whether it's in your leg, arm, back, or neck) and the hard roller will apply pressure and massage the sore muscle. It's basically a massage ball, but with a convenient grip that fits nicely in the palm of your hand for easier positioning.
My partner, Elle, and I started using the Harmony Roller after friends of ours showed off one of theirs. We found it was a really soothing way to get the knots our of our shoulders after a long car trip. Of course, being the sort of curious people are, we naturally started experimenting with the roller.
One neat feature of the Harmony Roller is it can be warmed slightly or cooled (even frozen) and it will still work smoothly. Elle discovered she really likes the feel of the roller on her back after it's been in the fridge for a while. Expanding on this concept a bit, we found that the Harmony is great for hot-n-cold sensation play where something like warm wax is dripped on the skin in one area and the cold Harmony ball is rolled across another patch of exposed flesh.
We also discovered the Harmony Roller makes a good addition to other forms of play. For example, it makes for a relaxing counterpoint during a light spanking session. Elle quite likes the combination of a cool roller tracing lines over her sore back muscles while my hands massage her and smack her bottom. (Admittedly this is a challenge for me, akin to patting my head and rubbing my belly at the same time, but it's a great experience when we get into a rhythm.)
The Harmony Roller is a great little relaxation aid and, in situations where you want a soothing sensation, it's also a cool toy to have during foreplay. We particularly like exploring hot and cold temperature ranges with the Harmony. The roller has a low price tag too so this is a great gift for a friend or a stocking stuffer.