Most efficient Bard Rotation DPS wise

[Viridiana]

It does, because there is a chance (a fairly high chance, actually) of a tick happening before the second DoT is applied.

Thus, you always want windbiter to be applied first. This is true unless the thing would die in under 5 seconds, in which case, why didn't you just use 2 heavy shots lol.

Less than 2 ticks left: Heavy
2-4 ticks left: Venomous->Windbiter->Heavy
More than 4 ticks left: Windbiter->Venomous->Heavy

Assuming you actually care enough to break it down that far.