Dexter told Delilah that she is doing a good job washing his back, but that she missed a bit on the right. He also told her he really appreciates her help because his big belly makes it a big hard to reach back there himself.
Delilah said it was no problem. She actually enjoys doing it and she likes it when he washes her face in return. His sandpaper tongue is better than any exfoliation product in the stores.