Despite her horniness, Jeff needed to give herself some arms at the very least! Wings are nice, but dexterous fingers would make everything a lot easier. She stood in front of the computer, watching the screen with her human head, using her tail to awkwardly move the mouse and her dick to slowly type in the change she wanted: add one pair of arms.
And then, with no fanfare at all, she had a pair of arms below her wings.
Now that she could type more easily, she could devote her tail-head's full attention to the computer while her other two could focus on her sexual urges. "...Huh," she thought. "Multiple brains means multiple attention spans? That could be useful."
For the next change, she moved her wings to her back. They were getting in the way of her arms, and besides, the angel look is more appealing than the harpy look, in her opinion.
Except, now her topmost shoulders had nothing on them. She was about to move her arms up, but... as the old adage says, if it's worth doing, it's worth overdoing, so instead she added a second pair of arms. Besides, having two hands for the keyboard and still one left for the mouse is useful.
She thought for a bit on what else she could change. Could her body's function be improved more, or was it time to focus on improving her looks? She could certainly think of a few ways to be sexier...