Eric "Badlands" Booker has chugged just about everything under the sun ... but there's still one liquid he REALLY wants to down at an insane rate -- telling TMZ Sports it's a drink you can't find just anywhere!!
We caught up with Booker as he prepares to defend his title at the Nathan's Famous Lemonade Chugging Contest this July 4 ... and he revealed a non-alcoholic apéritif called Beverly -- a Coca-Cola product -- is atop his wish list.
"I think it's from Italy or somewhere in Europe," he said.