on both of em, then Soul Swap ( unglyphed) when one dog is taunted away.
e.g. ( for 25m): dogs A & B are tanked together on tank 1, while dog C is on tank 2 and dog D on tank 3. If dog B is taunted by tank 2 -> tank 1 has dog A on him, tank 2 has dogs B and C on him, tank 3 still has dog D on him -> soulswap dots from dog A( the one left alone) to dog C ( the one that had no debuffs on him).
as an extra, you can try to keep Corr only on dogs A and D ( if you can). this allows for more shards regen -> more haunt uptime.
keeping other dots rolling on A & D is a dps loss, considering they take 90% less dmg when the dogs are tanked apart from any other dog.