Romeo and Juliet (Act 2, scene 1)
If love be blind, love cannot hit the mark.
Now will he sit under a medlar tree
And wish his mistress were that kind of fruit
As maids call medlars when they laugh alone.
If you’re ever reading Mercutio’s dialogue and wondering what the @#$% he’s talking about, odds are the answer is “sex.” In Act 2, scene 1, Benvolio and Mercutio are looking for Romeo, who is presumably off canoodling with his mistress. Mercutio references the medlar fruit, which was in those days widely considered to look like genitalia. He then proceeds to make the joke even more explicit for anyone who didn't get it, simply because he’s Mercutio and that's what he does.