Honestly, it really depends upon the person. For a long time I avoided it with my wife because she can be very sensitive and my shorter hairs would be more painful to her than anything. I would still nibble carefully with my lips when I just had stubble, but one time I wasn't thinking and nibbled her sides with long enough hair that it couldn't be avoided. She shrieked loudly and actually scared me, thinking I had hurt her or that something was wrong, but we both learned that her sides are extremely ticklish to that prickling sensation. Over time, many spots on her have shifted to be more ticklish than painful with it, but it still depends upon the spot and length of my hair on that spot. It seems to vary widely for different people. Obviously the shorter hair is going to be more stiff and prickly and the longer hair is going to be softer and more feathery. Which works best just depends upon the individual. Speaking of individuals, each individual's hair has a unique thickness, texture, stiffness, density, etc., so what one ler has that might be very effective on a lee, what another has might be ineffective, or even painful. Tickling is almost always a game of testing to find out what works between two individuals. In a lot of ways, that's the fun part for me.