Butt-lifting jeans are a success in Colombia, reports the BBC, and the innovation is heading north: "The decorated butt-lifter has become the archetypical Colombian jean, a product that has reached markets outside the country."
"It is exclusively Colombian," says a proud Mr Rivera.
The name says it all – the design has a few tricks to shape the buttocks of the wearer.
There are at least three secrets that make the butt-lifters work, and they can be seen extensively in the Gran San shopping centre:
A high waistband that covers the stomach
More cloth in the buttocks than other jeans
Pinched in one, two or three places above the back pockets or under the waistband, to shape the excess cloth
"It has been perfected over time so now the competition is to see who can lift more," says Mr Rivera.
I can't wait to buy my first pair of butt-lifting jeans. Recommend me a brand of butt-lifting jeans.