these hips are free hips. they don't like to be held back.
In fact, the speaker is so uninterested in "petty places" that she doesn't even allow them to have their own line. They have to share space with "these hips" once again!
What does get its own line is the assertion that the hips "are free hips." The speaker doesn't even need to describe the things that might try to hold her hips back, because, well, they aren't even worth mentioning. It's pretty clear that they're nothing to worry about.
We've said it before, but we'll say it again here: there's a clarity to Clifton's language. She's not wrapping her language with lots of extraneous words or turns of phrase. Ironically, she uses less (word-wise) to describe more (her hips, that is).
these hips have never been enslaved, they go where they want to go they do what they want to do.
It's not totally obvious, but we're guessing that Clifton is referring to women who actually have been enslaved – from black women in America to the sex slaves who are still trafficked today. Sadly, slavery is nowhere near a thing of the past. And, as Clifton makes clear, the sorts of power and enjoyment which our speaker experiences when she thinks of her own body are only possible because she's free.
You wouldn't think that this poem is necessarily political, would you? After all, a poem that's ostensibly (read: apparently) just about one woman's body. As it turns out, the female body is the subject of a decent amount of political controversy. From sex trafficking to abortion to pornography, there's plenty of attention paid to how and when and where a woman's body moves in the world.
Given all of this attention to the female body, it's rather incredible that our speaker can remain so fiercely optimistic about her own body's freedom. She definitely is optimistic, though – and, moreover, she's confident that her freedom is secure.