The speaker introduces herself as a "hip song mistress," a playful title that suggests she is both a performer and a woman in charge of her own life. Instead of giving a street address, she says she lives at "a waterfall / & grove of young / pines." It's a funny, boastful way of saying she belongs to the natural world rather than to any ordinary house or town.
The rest of her self-portrait is just as relaxed. She "amuses" herself with stallions, which could mean real horses or something more suggestive, since the poem leaves that open. She "sports" now and then in a thin white dress, a phrase that feels both innocent and a little teasing.
The mood is carefree, confident, and sensual. There is no worry or explanation here. The short lines and the lack of capital letters make the voice sound casual, almost like a quick, cheeky note. The speaker seems happy to be wild, independent, and exactly who she is.