It can have two interpretations, the most common and least understandable is "to be fresh, jovial, happy", which with a little imagination can be understood as an opposition to "being like a raisin" (wrinkled, consumed). The other is "being drunk", which can come from an association with the grape as the origin of the wine, or from a confusion from "being like a vat".
* Only one "like" per meaning and day, the more "likes" the meaning will appear higher in the list
