Alright, the person who does this IC course in the south of Belgium is actually the one who trained the vet. I called the vet, and problem is the person's technique seems to be ok, but doesn't work well for everybody, and the course is quite expensive for someone who doesn't wish to use the skill professionally: it's 120€ per day for three days of "introduction course", so that's roughly 380$ for the whole course. Plus a budget for food and hotel.
The vet gave me names of people who uses a better technique (the "Silva" technique), and apparently give cheaper lessons too.