It's act 3, scene 1 and the players are getting ready to rehearse Pyramus and Thisbe. The forest clearing is the perfect location as it can double up as a stage. And the hawthorn bush can be used as a handy dressing-room.
Quince wants to make sure that the rehearsal goes off without a hitch and is performed exactly as it will be before the Duke on the big night itself. This means that every last detail should be just right. But this concern for authenticity sparks off a debate among the players as to just how realistic they should make their performance. Bottom's worried that if Pyramus has to take out a sword to kill himself, then the ladies in the audience won't be able to stand such a gruesome spectacle. However, he plans to get round the problem by the simple expedient of announcing to the audience that he's not really Pyramus at all, but simply Nick Bottom, the humble weaver.
As for Quince, he insists that moonlight must somehow be brought into the chamber where the performance will take place, though he doesn't yet know how. The reason for this is that, in the original story, Pyramus and Thisbe first met by moonlight, and as Quince and the other players want to keep it real, then the same thing must happen during the performance. The only problem is how. Thankfully, a quick consultation of an almanac shows that the moon will indeed shine on the night of the scheduled performance. All the players need to do is to ensure that a window is left open in the big hall where they'll be performing to let the light of the silvery moon shine through.