Mental exercises?

Yes there is something called the urge-surfing technique which has been shown to be effective. I got this straight out of a book called the science of self-discipline:

Here are the steps:

1. Take a few moments to notice where in your body you are experiencing the urges. Just as hearing music might give you an urge to tap your feet or bob your head, most urges can actually be felt in the body if we have awareness.

2. Once you connect the urge to the place in your body that it's felt most strongly, focus your attention on that area. Observe the sensations you have there.

3. Spend 1-2 minutes noticing your breath.

4. Imagine that the sensations you feel as a result of your urge are a wave. Watch that wave rising and falling as your urge peaks and subsides.

5. As the urge inevitably passes, take note of its transient nature. The next time an urge arises, you'll be that much more confident in your ability to ride it out to its conclusion.

What's important to take away from this experience is that everything you think and feel is temporary, including desires. When you forget that fact, cravings and urges can feel overwhelming. But if you are patient and confident in your ability to ride out a temporary urge until it passes, you will find that it's far more effective than trying to distract yourself or battle the urges head-on.

And that's it. Stay strong brother!