Is Kuroko no Basket: Last Game NG-shuu hentai?
No
Rated PG-13 (Teens 13 or older) on MyAnimeList and not tagged as Hentai.

Special · 2017 · 1 episodes · PG-13 - Teens 13 or older
Comedy, Shounen, Sports, Team Sports
Animated bloopers, based on the extra section of the original manga, included with the BD/DVD release of Kuroko no Basket: Last Game.
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