This poem, written in free verse, more closely resembles the Native American tradition of oral storytelling, rather than a more structured, conventional poetic style. Though the poem is unrhymed and unmetered, its rich imagery and vivid descriptions are designed to sound terrific when read aloud. So, while a pair of lines like "You saw me drag toward you," and "Oh touch me, I murmured, and licked the soles of your feet" lack a regular meter or rhyme scheme, their variation in length and tone make them sound and feel natural when spoken. The same could be said for the stanzas. After three regular five-line stanzas (called cinquains in the poetry biz), we get a four-liner (a quatrain) to narrate the abduction. The change in form here goes along with the change in narrative: from creepy set-up to climatic (and equally creepy) climax.
Hey, who says you need to write in perfectly rhymed iambic pentameter to give your readers nightmares?