Its when you wipe your ass after a particularly filthy dump and you get a shit stain your thumb knuckle.
I was pleased to finally get the key to the executive wash room, however Stan Phillips was not pleases to see that I had a shit stained thumb knuckle when I shook his hand at the share holder meeting.
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.
When a manwill search for hours to find something that is laying out in the open on a table. Items are often easily found by a women.
Man: "I have been searching for hours for keys."
Woman: "You mean the ones sitting there on the coffee table?"
Man: "Where?"
Woman: "Right there in the middle of that table."
Man: "oh, must have been Male Pattern Blindness"