DO NOT LOOSEN YOUR ELBOW there is a lot of history in this expression. I'm going to start with fantasy and tradition. In Mexico and Argentina an elbow is a stingy person. It is said that the origin is due to the fact that Mexican ranchers went to the United States to sell their animals. When they returned, they kept the coins in bags that they made and got under the belt to take care of the bandits. So that they did not sound they pressed their elbows against the waist. It is also said that when the gunmen learned of the ruse, they were told to "loosen your elbows". The other story comments that the coins were kept in the pockets and that to take them out it is necessary to fllect the elbow, so not loosening the elbow was synonymous with not wanting to put your hand in your pocket and be stingy. The third version is that "elbow" is an apheresis of greedy, a term synonymous with stingy. It is easy that it was created as part of the Spanglish spoken on the border where Texans could not pronounce greedy and simplified it. But the latter are my assumptions. . .
