Responsible risk in gambling is basically using amount that you can afford to loose, gambling wins are by luck so you need to minimize the risks. We don't have any control over the outcome of our gambling results, the only thing that we have a control over is the amount that we decide to use. The higher the amount that you use for gambling the higher the risks, the lower the amount the lower the risk so we need to determine the level of risks that we're comfortable with. Gambling is not like a business where you're sure of making profit when you put money into it, there is no guarantee of wins so it's better to gamble responsibly by reducing the amount to something that you can loose.