Ashes to Ashes how uneven they burn

[perrymedik]

Hey just looking for a little advice on how to keep a cigar ash from burning unevenly. Is it something I am doing or is it just the nature of the cigar? Some times the bottom will burn further back then the top or vice versa, or it will do it on the sides as well. Do I need to roll the cigar after every puff, keeping it in constant motion or what? It doesn't happen all the time, nor have I noticed it consistant with any particular stick.

Advice is greatly valued!