The inner labias (labia minor) of a woman. Especially if they are not separated.
Hey girl, that's a nice baconstrip!
A shit stain on the underwear usually caused by digging fingers into the ass to scratch out an uncontrolable salty peanut (See salty peanut). Also known as a skid mark.
As she folded the laundry she noticed a large baconstrip in her boyfriend's underwear.
He decided to not buy white underwear anymore, because of his baconstrip making problem.