birth control pants

These are any pair of pants that will cause potential mates to not want to have sex with the wearer. A typical example would be a tight pair of jeans that have some sort of weird design on them and are worn by a straight male. However, there is not just one style or brand of pants that are birth control pants, and the exact definition can vary across cultures and time periods.

Katie: “I was attracted to Johnny until I saw him wearing those weird skinny jeans.”
Jenny: “You mean his birth control pants?”

Mark: “I wear my birth control pants out to the bars just to be safe.”