What does it mean?

[Kuromaku]

Can someone help me understand this one?

Is that a specific grammar point v-past + v-かけ or just an expression?

[nekoyama]

I don’t know if there’s something special. Isn’t it just “the half-drunk drink you drank was my juice”?

[Kuromaku]

I guess I just didn’t piece it all together… thank you!
Now it seems so obvious…

[mrnoone]

@Kuromaku @nekoyama
By the way, we have grammar point about that on bunpro

[Kuromaku]

Well, it’s not so much this specific grammar point, but rather putting it all together into a coherent meaning