Thank you both for your answer!
@Kathryn: yes and no it is similar, in most cases these people call theirself shamanic healer, claim to be ascended masters ... the whole new age package and since about 1-2 years the "mother-drum" and shamanism and "earth-healing" is the new seller.
However they do not tour with these drums they use just a big frame drum with about 1m in diameter (40-50 inches) for their healing sessions. Either in combination with massages or alone.
And there are workshops in which the people learn to drum or construct their own drum. Which is in my case a nice thing as long as they do not put some feathers on it and call it to be from native origins.
I mean I love drums, and have a couple of them mostly in the style of a djembe, but I never heard of a "mother(grandmother) drum", probably it is the diameter which makes it to a mother drum - well I don't know.
@earthw7
as long as I know at their sessions they do not sit on the drum they lay under it *g