I tightly stretched my nutsack around her face ear to ear and used my flashlight to illuminate the inside of my scrote within her field of vision. She exclaimed it was the most colorful batsignal she'd ever seen.
Someone or something that bites your ankles.
To a postman, an ankle biter is often known as a dog.
To an adult, an ankle biter may be a toddler.
To hikers, an ankle biter is sometimes a tick.
And so on.