This word is to be applied when an awkward situation arises. It is to be used when there is no comeback to a primary "rip". It is an acknowledgement of your defeat in the certain context.
There is no other word that can be used in the same context in the history of the English language.
In changing rooms after a rugby match, all in shower.
"Mate! Your cock is so small!"
When something foolish is done.
Man trips over infront of a group of 5 10/10 girls. "Riiight" is the only way of him looking at the situation with a bit more self-respect.