Barbershop Quartet

Barbershop Quartet is a group of songs the boys sang in the Season 21 episode "Hummels & Heroin".

Background
Stan decides to steal Ms. McGullicutty's hummels in order for his grandpa to become the "head bitch" at Shady Acres, so the other boys create a distraction by singing some songs in a barbershop quartet style. The residents react to the songs in extreme distaste and eventually leave.

Insane in the Membrane
 Cartman: I'm insane in the membrane All: Insane in the membrane Butters: Insane in the brain All: Crazy insane, got no brain Cartman: In the membrane 

Milkshake
 Cartman: Myyy Milkshake brings all the boys All: To the yard And they're like [Pops] It's better than yours Cartman: Damn right [Pops] All: It's better than yours Cartman: My hot milkshake 

Rape Me
 All: In the cool, cool winter Cartman: Rape me All: In the hot, hot summertime Rape me, my friend 

Two Princes
 Cartman: If you All: Want to call me baby Cartman: Just go ahead now 

When I Come Around
 All: No time to search the world around When I come around When I come around Cartman: I come around 

Trivia

 * Each of these songs are real songs, sung in a barbershop quartet style.
 * Insane in the Membrane by Cypress Hill
 * Milkshake by Kelis
 * Rape Me by Nirvana
 * Two Princes by Spin Doctors
 * When I Come Around by Green Day