Swallowing was the process of moving food or drinks from the mouth down the throat.
While under the forcible control of Parmen and the other Platonians, Spock sang a song which contained the lines, "Take care, young ladies, and value your wine. Be watchful of young men in their velvet prime. Deeply they'll swallow from your finest kegs. Then swiftly be gone leaving bitter dregs." (TOS: "Plato's Stepchildren")