Apart from, say, using trick to give lagging tail to the opponent.
Actually, there aren't too many ways to use it. You can have a Pokemon with sturdy hold it and then use flail for a LOT of damage. Or you can trick it to the opponent. But still that isn't too many ways to use it.
Actually, yes. You can double Payback/Revenge's power since you move last and something will probably attack you first. (provided you can survive the hit) And a Sturdy Pokemon/or any Pokemon who can hang in there when the opponent hits you hard can use Flail for a TON of damage. The last thing, like AwesomeEmboar13579 said, is using Trick, Switcheroo or Bestow (When opponent isn't holding anything) to give it to the opponent.