Characters
Ooh, gang, didja hear that? A bonus day of class plus Cordelia! Mix in a little rectal surgery and it's my best day ever!
— Xander ‧ Buffy the Vampire Slayer
Behind the line May contain spoilers.
Our reading
An editorial interpretation.
This is sarcasm played as excitement. The speaker cheerfully lists an extra day of class and an encounter with Cordelia as treats, then caps them with rectal surgery, so absurd an add-on that the pretended delight collapses. The joke is that this is plainly a terrible day.
Context reviewed