Amber Rose & Blac Chyna: Great BIG Tails ... and Feathers at Carnival

The entire island of Trinidad is waking up with an ass hangover -- courtesy of Amber Rose and Blac Chyna's awesome Carnival appearance.

The BFFs were front and center for parades all day and night, and fans captured the action from ALL angles. But one was more popular than others ... obviously.

Ass Wednesday, indeed.