Although advertised as a massage toy, personally I don't think that this would be very useful in massage. It becomes hard when fully activated. It does, however, do an amazing job warming in a general sense. For that reason, I use this item as a hand warmer on very cold days.

I play a sport outdoors and on cold days I just slip one of these in one of my pockets if it's extremely cold to keep my hands warm when I'm on break. It works incredibly well and stays warm for quite a long period of time. Activation is easy- just flick the disk and immediately you feel the warmth come out. You can even see the reaction happen inside the warmer, and the liquid starts to solidify, first into a soft somewhat pliable texture and eventually into a solid state.

It is a little bigger than I thought it would be, almost the size of my hand (although I have fairly small hands).

It is very easy to recharge the warmer, just stick it in a pot of boiling water for a little while and then take it out. It is very hot when it comes out of the water but as long as you let it cool off for a little bit it's fine. If it's in its liquid (recharged) state you could also stick it in the freezer and use it as a cold pack! Just temporarily though, I'm not sure how that would affect its warming reaction.

I LOVE the fact that is reusable, it makes me feel really good about not being wasteful- since I don't have to buy a bunch of disposable hand warmers and then throw them away.

Overall, this is a very versatile and useful item that I love. If you find a way to work it into your massages, that's great. I'll stick to keeping my extremities toasty in the cold.