The effect created by grooming a Shih Tzu‘s topknot in a way that gives its head a round and broad appearance is called the Shih Tzu “bubble.”  During examination in a show show,  a judge will gently slip an index finger under the topknot to determine the dog’s actual head shape.  Another slang expression is “racing strips” which refers to the two narrow colored strands of hair above the eyes that run from the roots to the ends. It’s most easily seen when the dog’s topknot is done up in a “bubble.”