Look up salty dog in Wiktionary, the free dictionary.
“Salty Dog” is nautical slang for an experienced sailor who has spent much of his life aboard a ship at sea. A salty dog is often given increased credibility by ship mates in matters pertaining to ship-board life and duties. Also known as an “old salt.” 
"Salty dog" also means ornery, as in the T-Bone Walker tune "Ain't Salty No More." In US folklore and song, salty dog has an older sexual meaning. For example, in the traditional song "Salty Dog Blues", the lyric "Honey, let me be your salty dog" translates to "Let me be your sexual partner."