1. When a girl hooks up with multiple guys in a short period of time commonly without a condom (hence burning wood, not rubber). Hit it and quit it style. As soon as she gets done with one guy, she is looking for the next.
2. Also could mean a sex session so long that the girl goes dry, and the friction starts to rub the guy raw, thus, creating a burning sensation.
"That girl is such a slut, I bet she burned wood all weekend."