Can I put a blanket or a towel on the mat to cushion it?

If you set a correct length and intensity for the procedure you should not feel any discomfort or pain. 

Really there are two type of procedures with the mat : 

1. Short and intensive for pain soothing or detox (from several minutes up to an hour)

2. Long and low-intensity for relaxation and sleep (1 - 10 hours)

If you would like to lay on the mat for a longer period or even sleep on it, this is best done slowly, adapting your body to the hardness and pressure. 

The first rule is to start with shorter procedures of 20-30 minutes and move forward slowly, increasing both length and intensity.

A half to one hour session at moderate intensity session may be enough to start.  

It is not a good idea to try to sleep on the mat all night, especially if your body composition is slim/low fat. 

Adaptation may demand a step-by-step increase of the time you lay or sleep on the mat, starting from half an hour and adding half an hour every second day, for example. 

Another way to decrease the pressure from the stones is to use a topper, towels, and/or blankets, on top of the included 3-D Air Mesh Pad and quilted cover, to make the mat softer. 

The cushioning layer should be as thick as necessary so that you do not wake up or experience pain or discomfort after sleeping. 

The MediCrystal 3-D Air Mesh Pad and waterproof multilayered cover are specially made to eliminate extra pressure from the crystals and hot stones in the ribbed surface of the mat. They are also great for protecting the mat from water spills, sweat, smell, dirt, bed mites and bacteria, with their built-in one-way-permeable membrane and special mesh layer, as well as for keeping the surface dry. We recommend them for when one is going to be sleeping on the mat or for longer, low-intensity sessions. 

So, to make the mat softer, we recommend putting several layers of cotton or bamboo sheets, blankets, or towels, or even a special washable waterproof protective cover on the top of these pads.

Far Infrared radiant crystal heat and negative ions will still travel through these layers to your body and you will be more comfortable laying on the mat.  

Naturally some of the energy will dissipate, but you can compensate this loss by increasing the temperature. Later, as soon as your body gets used to the mat, you can remove these extra layers one by one.