Crossword puzzle clue "body part that can mean applause or help when you give it to someone"

Body part that can mean applause or help when you give it to someone

Applause, applause, applause

Someone who can help you become someone you're not?

It can make mean men, but it can't make men mean

Mean, mean, mean

Mean, mean, mean

Give someone a book that they'll "give back to you when they're done reading," as I did with "The Wind-Up Bird Chronicle" over three years ago

It can help you get inside someone's head