"Calling downs" is a phrase with a tricky spelling. The first word, "calling," is spelled with the /k/ sound, followed by the long /a/ sound, and ending with the /l/ sound. The second word, "downs," is spelled with the /d/ sound, followed by the long /a/ sound, and ending with the /nz/ sound. This phrase is often used in horse racing, referring to the practice of a jockey urging a horse to slow down after a race.