Wicked is a real musical, that started production in May 2003 in San Francisco. The musical is based on The Wizard Of Oz.
The play seen in the episode is a parody and alludes to subliminal sexual suggestions in the performance.
Verse 1 & 2
Heaven knows we know what goodness is
O heaven knows wicked people aren't good.
From head to toe, she was just wicked people
Head to toe...
She wasn't good, to know what goodness is...
Take me away to that special place (that blowjob place)
Where people like us can all live free (Free to give blowjobs)
Take me away and let's live together
That's the place/blowjobs for you (blowjobs) and me...