I've been mislead... or have I?

[pseudogeek]

Dude. In the translation of (指切り) Yukibiri [Nico Nico Douga] I read last year, it said that the title meant "finger cutting". But today I saw one where it's "pinky swear". Then I googled and Wikipedia said it's literally finger cutting, but it's meant as a promise: you cross your pinky with another party's and it's implied that if you don't keep your promise you have to cut it off. So... which one is the song about?

Edit: Ok, now I understand! It is pinky swear! She says that to prove her love she's ready to go beyond the usual hair giving or nail giving and do the pinky swear. =_=