Were we not weaned till then? (2)
It's kinda creepy, but some of the sexual innuendo in this poem is linked to children. Whaaaat? We know, but think about it. Children are the product of sex, and once they're alive and squalling, they breastfeed. Plus, kids are naturally self-centered and focused on the pursuit of pleasure. Ever see a toddler with a cupcake? Yeah, well you don't want to. Get a room, already!
But sucked on country pleasures, childishly? (3)
In addition to providing a super-smutty pun, "country" also associates sex with a rustic bumpkin way of life. Contrast these crude pleasures with the expansive love in stanza 2 that makes their bedroom "an everywhere."
Or snorted we in the Seven Sleepers' den? (4)
Way to kill three birds with one allusion. By mentioning the Seven Sleepers, the speaker associates his former life with (1) children, (2) boredom, and (3) fear. Children and boredom make sense—mindless sex can be immature and boring—but what's this with fear? Could sex without love be scary? Is this fear of commitment? Fear that things will end? Fear that you care too much or not enough?