Is this one of the best forfeits?

I've used that as a forfeit before! It's perfectly harmless if it doesn't carry on too long. And it's a great forfeit especially for boys who often pretend they're not ticklish even though they are. For a 10 year old or something like that it 2-3 people should keep them still. The best spots to go for depend on the person although the soles of feet, ribs, underarms, sides and tummy are probably the best. But, the best spot that I've seen is probably the soles, just make sure they're bare and use fingernails and feathers to tickle. Have fun!