Starting at the Back mid-line, valley fold the block along the mid-line.
Fold the block back out so that the diagonal lines on either side of the mid-line remain touching.
Lather, rinse, and repeat to remove the marked triangles. If you find yourself with an angle as severe as the one I've got in front here, go back and check out the Adjustment for a Large Bust.
Fully folded out, a block that has been adjusted for a large bust looks a little less jarring. (The fact that we've now got a curved top edge goes a long way towards explaining why extreme boobs and doublets aren't such good friends!)