Traditionally tape is used on the floor to indicate where the talent is supposed to stand. This works but does leave tape on the ground and can damage the surface such as trying to remove it from a roll of seamless paper, or leave unwanted glue residue behind.
Kupo has come up with a better way. The Sausage Marker is a 10 oz shot filled "sausage", so it stays put even in windy conditions. The Sausage Marker is made from 1000 denier nylon for strength and durability and comes in multiple colors. It measures 6" wide and 1" in diameter. There is a grommet in the top of the sausage for easy transportation and storage. Just have your talent place their toes behind the sausage and they're in position.