Abbreviation for Blood Slut Levels. A technical term associated with a spike in sexual activity, often associated with feelings of guilt, sexual infections, and a risk of unwanted pregnancy. BSLs tend to peak in the early to mid 20s, then fall back down. However, there have been many cases noted that occur later in life (40-45), often involving women.
Margot's BSLs have shot through the roof this summer, she needs to settle down or risk getting pregnant.