It features a couple who went on a "Zombie 5K Run" together, at the insistence of the girlfriend. She'd done it before, but hadn't won yet. I guess she planned to pushed her boyfriend in front of a zombie or something in order to make it through to the end unscathed.
She enticed her boyfriend into coming to the run with promises of sex. After all, "Who wouldn't want to get involved with stirring the honey-pot when the world was ending?" (What a romantic, eh?) The couple stumble across an old rusty school bus and decide to "stir the pot," to coin a vulgar phrase.
They start making out and having sex on the old rusty bus when the predictable happens: a zombie shows up and reminds them that there is a virtual apocalypse occurring!
The girl freaks out and smashes her nose against her boyfriend's chin. Instant bloodbath. So much for the honey-pot...
The moral of the story? Public sex acts are bad. Even during a zombie apocalypse!
You can watch the whole segment here.