“Hey sailor”

SOOKIE: Not too much [make up].
LORELAI: No – just enough to say, “Hey sailor”.

A joke flirtatious catchphrase, supposedly from a prostitute or promiscuous woman (or man) to a male sailor, as if he is sexually frustrated after months at sea.

Lorelai is saying Sookie just needs enough make up to attract the attention of a desperate and not very fussy man. Not all that flattering, but Lorelai’s jokes rarely are.