Cheer Pressure : Season 7 Episode 12

As they press forward toward the next gym, fate reunites Ash and friends with Thatcher, who since their last meeting has been inspired to employ his Plusle and Minun in enhancing Pokémon battles by enthusiastically cheering on the battlers involved. When he actually witnesses Thatcher and other pep squad members at work, however, Max keenly suspects that they are being misled to not simply cheer competitors on, but actually breach official rules by misusing the abilities of their various Pokémon from the sidelines.