Where can I get a Lagging Tail in White?

Question

where I can found of from where I can get lagging tail in Pokemon white

Answer 1

I'm assuming that you're asking where to find a Lagging Tail. Correct me if I'm wrong.

In Black and White, the only way to obtain a Lagging Tail is for a wild Slowpoke, Lickitung, or Lickilicky. Each one has a 5% chance of holding the item. I suggest using a Pokémon with Frisk and Thief to acquire one quickly.

Source

Answer 2

In B/W, the Lagging Tail has a 5% chance of being held by wild Lickitung and Slowpoke. Lickitung can be found in Challenger's Cave and Slowpoke can be found at Abundant Shrine.

Sources: This, this, and this.