It's description read:
"... Each consecutive hit with a bow attack does progressively more damage to the target. Damage Bonus: 5%; Bonus Duration: 10 Seconds ..."
Now I'm wondering if this means:
1) Attacking one mob, my first shot does 100%, my second does 105%, third 110%, fourth 115% with no ceiling on the buff.
2) As above, but the % buff reached 10 seconds after the first shot will not be increased upon.
3) The second shot does 105%, as does the third, the fourth, and so on.
I may be wrong, but I'm pretty sure "consecutive hit" means against the same target. If you switch targets, you reset the buff. So not a "mob", but a single enemy within the mob.
It's great when used in conjunction with Flask of Lightning on a Tempest Archer and auto attacks.
Not sure if it applies with Leaping Shot against a dragon or giant, where multiple hits may occur. Probably not.
I think (2) is closest, but I'd state it as, "first is 100%, second is 105%, third is 110%, until 10 seconds elapses or target is changed, then back to 100%".
Also, it might not be +5%. It might be x1.05. So, "First is 100%, second is 105%, third is 110.25%, fourth is 115.7625%, etc."