Tybalt: You shall find me apt enough for that, sir. And you will give me occassion.
Mercutio: (walking away suggestively) Could you not take some occassion without giving?
Father Lawrence has a moment of this too:
Father Lawrence: Young men's love then lies not truly in their hearts, but in their (momentary suggestive pause) eyes.
All of the cute little allusions to Shakespeare's lines dotted here and there as ad slogans. The best one: "I'll send it posthaste!" In the movie, "Post-Haste" is a courier service, like FedEx (note the typeface).
The Montague boys leering and shouting 'I am a pretty piece of flesh'... at a group of nuns.