I've never heard that rule, but I haven't played extensively either.
So it is the word game where players take the last syllable and "ni" just go straight to the recently made offensive word.
I wonder if there is a word that ends with "cun", then the chaining can be cun-tasaur. Or "mo" to make mo-therfucker.
There is ki-sama, ya-ro, kin-tama, chin-ko, man-ko.