My boyfriend says that he could make a horse call by twisting a little pop cap - the tops on cans. He explains how you can get the cap into shape by biting part of it then pulling the piece of metal down. After bending the metal, he says that you place the bent pop cap on your lips and itll make a horse call. He then yells here horsey horsey horsey horsey! at the horses. - nyasuis. How to make a homemade horse call to lure in horses. Man shows her girlfriend how to do a horse call using a pop cap from a beer bottle, he bites the cap to bend it then positions it on his mouth but instead of hearing a whistle he shouts to call the horses