Victim of Impulsivity
Do not become a victim to 'impulsivity'. Pressures to perform or do well in studies may lead to over-eating for some people. Coveting for something that is not yours may lead someone to attempt to steal. Those actions are acts of 'impulse'. Make sure you learn to manage your thinking before you act. See below.
Next time you feel the urge or impulse to do something you know is not right, you can use the 'Traffic Light' method to help you. Red means 'STOP'. Stop what you are tempted to do. Amber means 'THINK'. Think about the consequences and effects upon yourselves and the people around you IF you fall victim to your impulsivity and do (or say) the wrong things. And once you considered carefully, make sure you respond rightly instead. i.e. 'GO' the green light.
In the example above, you could have asked for money to buy the things you want, (note that you may not always get what you wanted), but if you asked and got the money to buy the pens, you need not be afraid to be caught! If you managed your impulsivity with the urge to eat when stressed with schoolwork and instead went for a walk to relax your mind, you will end up healthier and fresher when you get back to work later on.
Do not simply act (on impulse) because you feel like it, or think like it or want to. Sometimes our feelings can fool us if we do not consider them carefully. So remember the TRAFFIC LIGHT method. Its easy.