When does team rocket get lickitung?

Team Rocket never actually gets Lickitung in the anime. While they do encounter one in the episode "The Poké Ball Scammers" (Season 1, Episode 22), they only do so to try and steal it from a trainer. They ultimately fail and end up with nothing but a bunch of fake Poké Balls.

There are some instances where Team Rocket acquires other Pokémon, but Lickitung isn't one of them.