To render one's anus or vagina in a graphical state of distress, as a result of a
particularly violent bowel movement or penetrative
intercourse.
The
description comes from the similar appearance to the ripped edges of a windsock (an item of metrological equipment used to establish wind speed/direction) as used at airports/flying schools, etc., which have become tattered as a result of excessive weather conditions.
"God, that curry
last night was awesome - my arse puckered starrusty sheriff's badgechocolate
tea towel holder this morning was like a tattered windsock"
"He was
hung like a horse; my twat vadgegrowleryeti's welly looked like a tattered windsock afterwards"