Marks vary from bottom to bottom (pun intended) but if you hit hard enough, most anything will leave a mark. You can minimize marks by doing a very thorough warm up and bringing lots of blood the surface of the skin. This acts as a cushion. Wearing pantyhose during a caning will also minimize marks but often the cane just glances off the tight hosiery and it's a bit disappointing, at least to me. The cane leaves marks by "wrapping" the skin around the cane and the tightness of pantyhose helps prevent this - but it is not fool proof. If you absolutely cannot be marked, stick with electrical.