Liam

dad lore

"Egg" is a term used in the trans community to refer to a trans individual before they realize they are trans. It is a metaphor for an unhatched stage of life, where "hatching" is the process of transitioning (either through active effort or through internal mental processes). There is a linked idea of "coming out of one's shell" or "coming out" in general, but one's status as an egg is not inherently linked to being openly trans or closeted.

The "pre-transition" sets up this part of the joke, related to the word egg.

The rest of the set up justifies the idea of "eating lads" setting up a vampire recounting her murders.

The end result is the summary phrase: "When I was an egg I ate four dozen lads." This is a direct transposition of the phrase "When I was a lad I ate four dozen eggs." This is a famous, (and much memed upon) line from the song "Gaston" from the late 20th century animated Disney Movie, Beauty and the Beast. In it, the titular Gaston, a beloved and small-minded stereotype of excessive masculinity, is lauded with praise for his manliness.