Simple question

[sarah thorne]

Smacking the skin (buttocks or anywhere else on the body) puts pressure onto the tissue below the skin. When you put pressure on an area of tissue, you cut off the blood flow (in spanking, this would be momentary) to that area by physically collapsing the vessels which deprive that tissue of oxygen. In essence, when the 'pressure' is off, blood flows to the tissue (surface of the skin, obviously and red color) into the area, almost as if the tissue were blushing.

Keep smacking the bottom (continuing pressure) and you just cause more blood to flow to the tissue to supply it with oxygen, therefore creating more redness.

sarah