A woman who gives sexual services and affections but is also encumbered with a lot of debt (student loan debt, credit card debt, etc).
Similar to a gold-digger, but one motivated largely through her debt. These women usually do not reveal their financial situations until late into the relationship, hence the "bomb".
Tom: Are you still seeing Rachel?
Steve: Nah man, she gave good head, but turns out that tramp was a debt bomb. She wanted me to start paying her credit card bills.