To be unfaithful to one's partner e.g. in an extramarital affair. Named after South Carolina Governor Mark Sanford, who was said to be hiking the Appalachian Trail, when actually he was visiting his mistress in Argentina.
To have a sexual encounter or affair, named after the infamous disappearance of South Carolina Governor Sanford, originally thought to be hiking the Appalachian Trail, but was having an extra marital affair in Argentina.
A euphemism for a long-distance bootycall to Argentina.
Additional points if you 1. are a politician 2. lie to an entire state/nation 3. Hail from South Carolina 4. Utter the words "I have just spent the last five days of my life crying in Argentina".