pinky sweater
A pinky sweater is a rare, complex, and sacred binding agreement. Two consenting parties perform strenuous calisthenics with their respective pinky fingers until clammy enough to be deemed "sweaty pinkies", then, while maintaining sweaty pinky-to-pinky contact exchange unbreakable vowels of commitment to a predetermined cause.
Priest: "Do you, John Doe, take thee Jane Doe to be thy bride in holy matrimony, as long as you both shall live?"
John Doe: "I Pinky Sweater it"
John Doe: "I Pinky Sweater it"