The song and dance then begins. In the lyrics of the song the fairies warn the spiders and lizards and snakes to stay away from their Fairy Queen while she slumbers. The reference to Philomel (in line 13) simply indicates the nightingale, the singing bird of the night: its sweet chirping is to provide the music for their dance (perhaps a musician with a pipe plays a chirping melody at this point). The name of Philomel also complements the Greek mythology that forms part of this play. According to the myth, Philomel was a woman who was raped and then transformed into a nightingale so that she would not have to face her shame in human society. The myth also connects to the references to lust elsewhere in the play.
The words of the song, though, are actually less important than the pleasant music and dancing that is taking place. This is spectacle. This is entertainment for the audience. After all, people do not often have a chance to see fairies singing and dancing.
After the fairies complete their song and dance, they leave the stage to let their queen sleep in peace. But then Oberon appears and puts the magical love potion on Titania’s eyes (line 33). Then the Fairy King exits as well.