This alliterative term originated with the Catholic Portuguese as 'Canhao do Coromandel' to initially refer to a large piece of ordnance in any of the numerous forts they built along the Coromandel Coast. When these Lusitanics later discovered the mythical gargantuan size and legendary powerful erection of the Dravidian penis, they extended the meaning of this phrase to refer to the imposing genitalia of the Dravidoid male. As these forts were taken over by later West-European thalassocracies such as the Dutch, French and British, variants of the term and its double meaning were usually adopted by these languages, and then by South Asian languages as well.
The term is frequently used in Hyderabadi Erotica, such as in the popular masala hit movie "Coromandel Cannons in Tight Aryan Fuddis (Vaginas)". In jokes, this phrase is often used alongside "Punjabi Pistol" and "Portuguese Pistol", to discreetly refer to, and simultaneously dramatize, the penis size differential between the Fair Aryan and Black Dravidian races. The phrase "Coromandel Cannon" is also often used to promote sex tourism to the Coromandel Coast, in exactly the same way that the term "Malabar Black Snake" has been used so effectively in Goa and Malabar.
Telinga: No, you Portoghalee boys don't have any guns.
Pinto: What you mean ?
Telinga: All you Portoghalee Boys have is a Portoghalee Pistol! This is a Coromandel Cannon (pulls Big Black Dravidian penis out of lungi).
Pinto (shuts up)
2. Sheikha (legs spread wide, beneath Sheikh Chilli): Mehboob (Darling), I can't even feel anything with your Punjabi Pistol. I think I will have to go to Hyderabad and find a Coromandel Cannon.
Sheikh Chilli (thrusting powerfully): Chalo (Come on), my Zubb (penis) is not that small!
Sheikha: It is compared to a Dravidian one!!
Sheikh Chilli (stops moving, silent as Zubb deflates and his manhood slips away)
Sheikha (laughing): And now it's more like a Ganges Worm than a Punjabi Pistol!
3. Caliph Akbar: Moolla Sahib, why are you so depressed ?
Moolla Do-Pyaza: My Bibi (wife) ran off with a Kala Shudra Goonda (black Shudra goon).
Caliph Akbar: That Haramzadi (Bitch)! But why she left you ?
Moolla Do-Pyaza: My Punjabi Pistol could not compete with his Coromandel Cannon!
4. "We use the Coromandel Cannon to break down caste barriers" - Slogan of Inter-Caste Sex Society
5. "The Portuguese Factor and Captain of Coromandel, Diego Rebello, took Coromandel guns and arrived at Satagon in his own vessel." - Indian Archives (Nat.Archives of India), vol.41 (1992), p.20.