What is Mercutio saying? More than prince of cats, I can tell you. O! he is the courageous captain of compliments. He fights as
you sing pr*ck-song, keeps time, distance, and proportion; rests me his minim rest, one, two, and the third in your bosom; the very butcher of a silk button, a duellist, a duellist; a gentleman of the very first house, of the first and second cause. Ah! the immortal passado! the punto reverso! the hay! He is calling Romeo unmanly. He showing his deep respect for Tybalt's fighting ability. He is teaching Benvolio how to sword-fight. He is criticizing Tybalt's lack of authenticity, despite his knowledge of custom.
Mercutio says Tybalt is greater even than the prince of cats, which suggests he is agile and fit. He calls him courageous and says that he deserves whatever compliment he can be given.
He wants to kidnap her and obviously she's not a ordinary woman, she can pull some stunts over him so he shoots at her waist to cripple her for the time being.
