If a dice is considered an exploding dice, you may re-roll it whenever you get a six, and add the original roll and the additional roll to the total result. You may re-roll the dice as many times as you can continue to roll a six.

Example
You have an exploding dice and you roll a 6. You re-roll and get a 6. You re-roll again and get a 5. The chain ends because you did not roll a 6 on the third roll. The total value of this dice is 17.