Sack Flaps are a rare genital disease that gives the unlucky victim an extra, saggier pair of nuts. This extra pair usually hangs lower than the typical pair.
Hey bro, do you have sack flaps!?? I could see them through your thinleggings.
A type a dog, usually black, that specifically has the name Sammee. That never shuts his mouth and loves barking. The place where usually a dog's checks are have being replaced by salmon like flaps.