We moderns might be surprised to see the Bible celebrating drunkenness, but here it is, plain and simple. Being in love in Song of Songs is like being drunk—but better. In 4:10, the groom actually says, "How much better is your love than wine." That's no frat boy.
Let's look at some examples to get a feel for how this image works:
"Your lips distill nectar, my bride; honey and milk are under your tongue; the scent of your garments is like the scent of Lebanon" (4:11). What do we have here? Luxury. Exoticism. And booze. And in case it wasn't clear enough, several lines later, the groom declares, "Eat, friends, drink; and be drunk with love" (5.1).
"Your kisses [are] like the best wine that goes down smoothly, gliding over lips and teeth" (7:9). Luxury? Check. Sensuality? Check. Intoxication? Check.
See how these metaphors work? They center on one sensual image and then link that image with love as a boozy force.