There is no way of accurately describing what the cane feels like. You just have to try it. For a first timer I would recommend no more that four of the best using a 70 x 1 cm rattan cane across the seat of ordinary trousers.
Cane sizes undoubtedly varied with time and place, and the age of the boys being punished. 70 x 1 cm rattan was probably typical for younger teens. I would be very cautious using anything longer than about 90 cm or thicker than 12 mm.