Word ment to imply that impromptu or spontaneous sexual congregation in an un-traditional location has recently or is currently taking place. The fact that sex is taking place is identifiable to bystanders within ear-shot by the clanking noise of one or more belt buckles being dropped to the the hard-surfaced floor. Origin of word: Kansas City, MO.
May also be used as a verb.
See also "merk" or "merking."
As I re-entered the party, I noticed my friends were gathered around the bathroom door and appeared to be listening intently. A party goer had just entered the bathroom with a random girl. A clank sound was followed by sounds of passion. Those near the door exchanged a knowing look, and several spoke in unison, "CLANK!"
"Hey Padrick, you broke my mirror when you clanked that chick in my bathroom during the party last night."