What is the difference between a priest and anesthesia?
The anesthesia takes time to put you under.
Priest vs Anesthesia
Explanation
Explain Bear
Okay, so basically, the joke plays on the double meaning of "putting you under." Anesthesia literally puts you under medically, but the joke implies a priest "puts you under" in a different way, which is lewd, and I won't be spelling it out because I am a respectable bear.