How does the punchline in this SMBC comic about "Vickrey-Clarke-Groves auctions" work?

Question

Saturday Morning Breakfast Cereal (SMBC) showed this comic today:

I'm not entirely sure I understand this punchline. Based on what Wikipedia tells me about this form of auction, it appears to be a blind bid auction involving multiple bidders and multiple items where the final payments may be lower than those that were originally proposed. At first read this just appears to be a joke about promiscuous conference guests, but SMBC comics generally have layered punchlines, so there's probably a layer to this comic that I do not understand related to how VCG auctions work.

Is there an additional layer to this comic that I don't understand due to my unfamiliarity with economics?

Answer 1

Hard to guess what exactly Wiener-Smith was thinking off, but I would hazard it is just about the exact rules of the Vickrey-auction. Such an auction (for a single good) is also called a second price auction. Everyone submits a bid, and the highest bidder wins, but they only have to pay a sum equal to the second highest bid.

In the context of the comic, perhaps each prospective romantic partner submits a position they would perform. The person of interest ranks these, and selects the partner with the most interesting proposal, but they will use the second most interesting position. The joke seems to be that you would be doing something you might be uncomfortable with.

Mind you, this would defeat the purpose of a Vickrey-auction, where a truthful bidder never regrets winning. The problem arises that while everyone orders monetary payments the same way - you want to pay as little as possible and have an individual valuation for winning - you may order other types of actions differently, with some bidder willing to do action A but not action B to win, while another bidder might be willing to do action B but not action A.