When you are at a party with your friends and you feel like fucking around. Walk up to a random girl, and ask her "Yay or Nay?" She will either respond with a "Yay", in which case you will proceed to hook up (make-out), or a "Nay", where you will feel brutally defeated.
Micah: Yo Adam, pull a yay or nay on that girl over there.
Adam: Nah brother, she'll say no.
Micah: Brother, stop being a bitch and do it.
(Walking up to random girl)
Adam: Yay or Nay, we hook up right now.
Hot Girl: YAY