The act of placing ones body in such a way in which arms are by the plankers side & all limbs are at full extension often performed on a unanimous object. The object in which the planker chooses to plank on is entirely the plankers choice, although the more unique the object often the better the plank. The planker usually immortalize the plank with a picture.
Bill: I have a great idea for planking!
Bill: Let's go to the gym and plank the basket!
Sean: Dude, you're sick.