1. A highly guarded and secretive goldmine of one's adultmaterial. Usually referenced in regard to a voluminous and particularly titillating collection.
Jamie (older gentleman): Have you noticed how there are less and less Fort Knockers around.
Shane (older gentleman): Yeah, with the internet now a days people are beginning to abandon the gold standard of porn, choosing to trade in papers and tapes for illicit web sites. I've heard one can get all sorts of diseases from sex, and now, viruses from the internet.
Jamie (older gentleman): Kids these days just don't understand. But alas the world is changing.
See tits, hooters, bazookas, bazongas... same thing.
Knockers have to be kinda big to deserve being called that.
Lil titties are better addressed as mosquito bites or zits
Likeelectrictoy trains, knockers were originally designed for kids, but are mostly enjoyed by grownups.