Dwi's tail language is most similar to a snake, in that their tail is very long and slithers back and forth on the ground. They don't do much communicating with their tail other than that a faster slither might indicate frustration or excitement. For the most part their tail is used as a weapon either to strangle, grapple or whip and is quite dangerous.
This tail language can be taken across pretty much any universe where Dwi has a tail (which is most of them)