So, if you and your buddy are flanking an orc, you both roll a d20+1d4 say, a 12 and 3. But, also, if you hit, the roll would also add to the damage you do. As an alternative, I was thinking it would work more like Bless granting a 1d4 bonus to hit (which would stack with Bless). So, I have one DM who loves flanking per the DMG and granting advantage on attacks is cool, but a little too powerful.
