A lot of vigor, determination, and motivation. A reference to an advertising slogan of the oil company Esso: "Put a tiger in your tank." The company had a tiger in its tank in the late '90s, a seemingly unstoppable juggernaut in the industry, but a series of awful business decisions and the economic crash led it to bankruptcy in 2013. The manufacturers advertise the energy supplement as being able to put a tiger in your tank when you're feeling tired.