And, the commands continue. The Oread keeps on telling the sea what to do. She starts in again on this pine business and continues her metaphorical way of speaking about the sea as if it were a forest.
We can't help but wonder: why is she commanding the sea? But this line isn't answering any questions, that's for sure.
A quick note on form: notice that lines 2 and 3 both end of the word "pines"—we call this a perfect rhyme.
This poem clearly isn't held together by a traditional form (no regular rhyme or meter here, folks), but it is held together by repetition, like these "pines" and the earlier "whirls." A poem can be all delicious and sound-y without the types of regular rhymes you'd find in a Shakespearean sonnet.
on our rocks,
Well, now we know where the Oread wants all this whirling to happen.
She's commanding the sea, with its piney waves, to come up to the land, where we're imagining a rocky shore. Notice that we have to fill in a lot of these blanks for ourselves, because of the poem's spare language.
And note that the Oread says "our" rocks. She's not the only one on this shore. But who is included in this "our"? Other Oreads? Other creatures who live on land? We can't really be sure.
But now we've got a better idea of what the Oread wants. She wants the ocean to crash down on the land, like she's begging the sea to exceed or escape the regular tidal patterns and meet her in the forest (an Oread is a mountainous forest-dwelling nymph after all).
And why does she want this? Our best guess is that the Oread is trying to unite two worlds—the land and the sea.