Reattach the yarn and purl your way back. Decrease by 2 stitches on each side of the next, and every other row, for 28 rows, until you have only 16 stitches left. Work in stockinette stitch for 13 more rows. Bikini Top Divide remaining yarn into two balls. We're going to make both triangles at once, because we're busy and summer's coming soon.
Directions are for a full coverage A, a comfortable B, or a scanty C cup.
If you decide you want more coverage or have a larger bust, just cast on 5 to 10 more stitches. These instructions will still work. Cast on 33 stitches for each triangle. Work in stockinette stitch for 18 rows, then start decreasing two stitches on each side of every other row for 16 rows, until you have nothing left. Alright, now you're really almost done.