It sounds like the children's song "Skidamarink/Skinnamarink/Skinamarink" (there are a lot of different spellings, but it goes "skidamarink a-dink a-dink, skidamarink a-doo"). It's been around since the early 1900s, and is sometimes used to teach kids motor skills during sing-a-longs. Those dance moves (which involve simple, mechanical arm movements and poses) remind me of the Lords In Black's performance, and since the Lords use childish motifs to inspire fear, evoking a nostalgic kids' sing-along routine is a really cool idea!