This hurts me more than you
The phrase expresses that while the child may feel physical pain, they should be aware of the fact that their parent feels emotional pain about being in the sad position of having to correct their beloved child in such a way. The phrase can be used in earnest, but also ironically or hypocritically.
Note that if the spanking is a hand-spanking, the spanker may in fact feel considerable physical pain in their hand after spanking for a while. The human hand is no less sensitive to pain than the human buttocks. A humorous reply from the spankee to "This hurts me more than you" is "Yes, but not in the same place."
- This hurts me more... (cartoon)