This indicates a character is playing with either their own hair or another's hair. This is generally frivolous, playful, or meaningless behavior. For example they might be simply twirling or flipping a lock of hair, making a "hair mustache", or "eating", ruffling, kissing or smelling their or another's hair.
If they are meaningfully working with their or another's hair for a concrete goal, instead use one of the following tags as appropriate: