Breeding carpet pythons behaviours help

[Demisnakes]

Hi I put my two carpet pythons together one male and one female. The female began wagging her tail for the first time immediately and after a while I saw what looked like dried blood on the newspaper. I removed the male but couldn't find any blood on either snakes. I cleaned out the enclosure then i found some more dried blood after a couple hours again cant find any blood on my female? What is it and anyone else seen it before?