“Hold your seahorses, Sagi”

This is based off of “Hold your horses” and basically means “wait.”

One of the earliest sources for the phrases is Homer’s Iliad (8th century BC)

‘Ἀντίλοχ᾽ ἀφραδέως ἱππάζεαι, ἀλλ᾽ ἄνεχ᾽ ἵππους:

Antilochus, you are driving recklessly, hold back your horses

(Ancient Greek source)