" So we have a deal,” she says.

“We have a deal.” I take my right hand off the steering wheel, spit in my palm, and hold it out. “Shake on it.”

The smile disappears, and she shrinks back toward the window. “Absolutely not.”

“Don’t be a wuss. Just spit in your hand and shake.”

“You’re disgusting.”

“It’s like signing a contract. We made a deal; now we swap spit.”

“It’s nothing like signing a contract.”

“There are other ways to swap spit. Do you want me to pull over so we can make out instead?”

She spits in her hand, takes mine, and shakes it firmly.

“Note to self,” I mutter. “Threatening to kiss the fiancée yields immediate submission to my will.”

“Ha,” she says, and wipes our spit on my shorts. “Gross.  "

― Jessica Martinez , The Vow