Sara's behind (warmup drawing thing).
Sara has never had much white on her backside, it's increased some over the years and while I'd like to give her the heart shaped white markings I'd guess people would notice the sudden change. Technically the white does extend up the center to the base of her tail via a thin strip it's not visible under most circumstances.
Backsides have always been a bit tough for me so if it looks a bit wonky it's because I don't draw them often (hence the warmup practice).