An enema is a procedure where you shoot saline up your butt into your rectum/large intestine where it liquefies your solid waste and it comes blasting out within minutes. It's like forcing yourself into a Mexican food-induced bathroom journey.
I know what it is, but the enema setting in the toilet is also labelled "turbo."
Explaining a joke is a lot like dissecting a frog. You understand its components and how it works, but it dies in the process.
