You did not say who you are playing in this scene.
Stage directions are in the language itself in Shakespeare. If you were to check the Folio, you would discover that there are only a hand full of stage directions as we think of them. What we have today are editors who have added the stage directions we have.
Ask yourself the mood of the scene. The teenage boys are on their way to crash the Capulet's party. How do you think these youths are feeling about that? Mercutio is the clown of the group and he keeps trying to lighten Romeo's mood. Romeo is still moaning and groaning about his unrequited love.
Remember these are teenage males and Mercutio is fond of making rude and suggestive jokes. Many of his jokes have to do with sex. Think of it as locker room humor.
Boys will be boys.