I was a bit confused by this statement as I remembered DS’s BSA first aid info on frostbite that you should NOT massage frostbitten areas. I went back and re-read what is in DS's BSA handbook and in the BSA first aid merit badge pamphlet regarding frostbite. Here is the info I found:

Frostbite is a condition that occurs when skin is exposed to temperatures cold enough that ice crystals begin to form in the tissues. A frostbite victim might complain that the ears, nose, fingers, or feet feel painful and then numb, but sometimes the person will not notice any such sensation. Grayish-white patches on the skin – indicating that ice crystals have begun to form in the top layers of the skin – are signals of the first stage of frostbite, or frostnip. With continued exposure, frostnip worsens and the freezing extends to deeper layers of the skin and to the muscles. Frostbite can be very serious, as it can cut off blood flow to the affected area and lead to gangrene, or tissue death.

First Aid for Frostbite

If you suspect that frostbite extends below skin level, remove wet clothing and wrap the injured area in a dry blanket. Get the victim under the care of a physician as soon as possible. Do not massage the area or rub it with snow. Rewarm the area only if there is no chance of refreezing. Expose the affected area to warm (100 to 105 degrees) water until normal color returns and it feels warm, and bandage the area loosely (placing dry, sterile gauze between fingers and toes). To treat frostnip, move the victim into a tent or building, then warm the injured area. If an ear or cheek is frozen, remove a glove and warm the injury with the palm of your hand. Slip a frostnipped hand under your clothing and tuck it beneath an armpit. Treat frostnipped toes by putting the victim’s bare feet against the warm skin of your belly.

Here is the link to the PDF of the merit badge pamphlet: https://docs.google.com/file/d/0Bxgvwk8HKLlHT0ZRalhQcHV2UDQ/edit?pli=1