The phrase refers to the developmental stage in Pembroke Welsh Corgis and Cardigan Welsh Corgis when their ears transition from a folded or floppy position to an erect, upright stance. This transformation is a characteristic physical feature of the breed.
Erect ears are a breed standard and contribute to the alert and attentive expression typical of Corgis. Historically, upright ears were advantageous for herding dogs, allowing for better sound localization and awareness of surroundings, crucial for managing livestock.