tailfirst

With the tail in front.

Adverb

  1. With the tail in front.
    • This change occurs during the first stage of parturition, and the orientation changes where 60–70 percent of the puppies are born headfirst. Changes in orientation leave about 30–40 percent are ^([sic]) born tailfirst....

    Antonyms: headfirst

Origin

From tail + first.