If a Pokemon is holding Lagging Tail but uses a priority move, what happens?

Question

Priority Moves that have +1 or more Priority. Here's a list:
Helping Hand|Pursuit (If target is switching)|Detect
Magic Coat|Protect|Snatch
Endure|Fake Out|Follow Me
Quick Guard|Rage Powder|Wide Guard
ExtremeSpeed|Feint|Ally Switch
Aqua Jet|Bide|Bullet Punch
Ice Shard|Mach Punch|Quick Attack
Shadow Sneak|Sucker Punch|Vacuum Wave

Answer 1

If a Pokemon holding a lagging tail and uses a priority move, the priority will be priorited (hope you understodd what I meant there), so If you take a Pokemon with lagging tail, and uses Quick attack you will go first. But, If you have higher speed than opponent and uses a+1 priority move (for an example) , while your opponent uses a +1 priority move too, you will still go last because of the lagging tail.
Sorry If this just confused you Even more XD, but you can read the source for an better example.

Hope I helped :)

Answer 2

It depends on which move it is. If its a move like helping hand, rage powder or bullet punch, it goes first. If its a move like quick guard or magic coat, the move will go second or last. Some of those moves priority is either 0 or -1. Ice shard and and shadow sneak have a priority of 0. The lagging tail makes you go slower but using a +1 priority move will either make you go 1st or last.

Comments

I just used Bulbapedia's list of priority moves :P
Shadow sneak still has a priority of +1 though.