Caught by Jessie after it ate all of her food she just bought during the Princess Festival.
At the Princess Festival Jessie used Lickitung in a battle against Misty where it defeated Ash's Pikachu, Bulbasaur and Brock's Vulpix but was unable to beat Misty's Psyduck who seemed to be unaffected by Lickitung's lick attack.
Lickitung was rarely used by Jessie in comparison to her Arbok, although, it was only by accident that it was traded with a Wobbuffet during the convention called the 'Pokémon Swap Meet' when Jessie was knocked backwards into a trading machine and Lickitung's Pokéball landed in the trading machine next to Benny's Wobbuffet.
Click here to see info on Benny's Lickitung.