Repetition is an important part of "homage to my hips." It adds a sense of rhythm and musicality to the poem, and also repeatedly draws readers' attention to the star of the show: the speaker's hips.
The speaker uses diacope in the first line, saying, "these hips are big hips." This spotlights the obvious fact that the poem is, indeed, an "homage" (a kind of ode or tribute) to the speaker's hips, but it also establishes a pattern that will appear throughout the following lines.
The speaker brings this sentence structure back in lines 5 and 6, saying, "these hips / are free hips." This line repeats the first's use of diacope while also serving as an example of anaphora, since the speaker once more begins a phrase with the words "these hips."
This happens yet again in line 8, with "these hips have never been enslaved," as well as in lines 11 and 12:
these hips are mighty hips
these hips are magic hips
The combination of anaphora and diacope creates parallelism that, in turn, makes the poem sound rhythmic and insistent.
The speaker uses more anaphora in beginning subsequent lines with the word "they," going on to clarify what, exactly, her hips do. Take, for example, the way lines 5 through 9 alternate between "these hips" and "they":
[...] these hips
are free hips.
they don't like to be held back.
these hips have never been enslaved,
they go where they want to go
This alternating pattern gives the poem a feeling of consistency and predictability. It also adds a certain rhythm to the speaker's words, making the speaker's language musical and celebratory. Finally, repetition helps the speaker's confidence and pride shine through.