Popular ethmology bases this term primarily on the wide usage of Sambar among South Indians. A secondary meaning, however, takes the thick, spicy & viscous liquid to be a representation of Dravidian sperm, & thus, by extension, of South Indian men.
The term is reflective of deep-rooted Dravidophobia & is founded on non-Dravidian disdain for chilli-laden Sambar & ultra-spicy South Indian Cuisine in general, both of which have been proven to cause ulcers among Caucasoid-Mongoloid people. It is esp. commonly used by racist sections of society across the British Commonwealth, incl. North India, Malaysia, Singapore, Sri Lanka, Britain, Canada & Australia. Among Indo-European & Oriental men, Anti-Dravidianism is often based on physical & sexual rivalry with 'South Indian Goondas', Dalit Panthers, Tamil Tigers or Andhra Black Cobra Gangs, & is further fuelled by emasculating Dravidian Penis Envy.
Chotu Chilli: Abbu, that's your car!
2) Bade Mian: I hate those ugly Thambis!
Chote Mian: I hate them even more, because my wife ran off with a Sambar Nigger!
3) "Hey, filthy Sambar Nigger, come here & lick my feet!" - 'Sambar Niggers' RSS Brahmin, topix.com 4 Nov 2010.
4) John Bull: Girl, if you ever get a Sambar Nigger boyfriend like that Polish actress Olga Sosnovska, I swear I'll throw you out of the house!
5) Ah Chong: That ugly black Ah Neh is just a Sambar Nigger!
6) Ram ka Aulad: Sambar Nigger, keep your claws off our fair Aryan women!
7) Pundit Iyer: Never go with a Madrasi! Sex with a Sambar Nigger is beastiality, & you'll be re-incarnated as a cockroach!
8) "You Tamil Nigger, why do you people have such an inferiority complex? Nobody can help that you people are uglier than Africans. Stay back in Tamil Nadu & east idli sambar! Disgusting Sambar Nigger!" - Vishnu, Re: Andhra People. 9 May 2008, mboard.rediff.com