Romeo and Mercutio don't fight. Mercutio fights Tybalt on behalf of Romeo (Romeo can't because Tybalt is Juliet's cousin). Romeo tries to "break up the fight" and while doing so Tybalt stabs Mercutio. Then Romeo fights Tybalt and kills him.
In Act 2, Scene 4 of "Romeo and Juliet," Romeo and Mercutio exchange witty banter as they wait for Juliet's Nurse to arrive. Mercutio teases Romeo about his infatuation with Juliet and his love troubles. Their dialogue is humorous and light-hearted, showcasing Mercutio's clever wit and Romeo's preoccupation with love.
They are hanging out when Juliet's nurse comes to talk to Romeo. Mercutio teases her and is really quite rude, whereas Romeo wants to talk seriously about marrying Juliet.
He doesn't. Mercutio is not in that scene, and Benvolio and Romeo do not part company.
Mercutio and Romeo make puns about names, love, and physical appearance in Act 2, Scene 4 of "Romeo and Juliet."
Actually, Mercutio is killed in Act III Scene 1 when he duels Tybalt. Romeo tries to stop the fight, by throwing himself between the two, but Tybalt manages to stab Mercutio under Romeo's arm.
to protect romeo
Benvolio is speaking to Mercutio at the end of Act 2, Scene 1 in Romeo and Juliet. They are discussing Romeo's sudden disappearance, as he has climbed over the wall into the Capulet's garden.
In Act II Scene 1 Mercutio satirizes Romeo's supposed love for Rosalind.
Mercutio and Benvolio trade insults with Tybalt. Romeo arrives, but refuses to quarrel with Tybalt (who is now his cousin by his secret marriage to Juliet). Mercutio is willing to fight, but is killed by Tybalt as Romeo tries to intervene. Romeo, enraged, pursues and kills Tybalt. Prince Escalus banishes Romeo.
Quite a lot really. Just about everything Mercutio says in Act I Scene IV is in response to Romeo's "heaviness".
Mercutio says this to Romeo in Act I Scene IV of Romeo and Juliet.
Mercutio meets up with Romeo and has a great time making fun of the Nurse.
Mercutio says it about half way through Act 2 Scene 4.
He reminds them that the Prince has forbidden street-fighting.