Khloe Kardashian -- Back in the Club ... TWERKING Hard on The Game

Khloe Kardashian gave Game an assful last night in Hollywood ... twerking hard on the rapper in the middle of a packed nightclub.

Khloe put on a clinic in Tru Nightclub with moves that screamed, "I'm single and ready to mingle" ... with Game's crotch.

While we've seen Game and Khloe kick it in clubs before ... we've NEVER seen them on the dance floor like this. They always deny they're together -- but there's no denying their genitals were together last night.

Khloe and Game had a chaperone -- Kris Jenner was also in the club -- but clearly they couldn't care less.

By the way ... Khloe, and her ass, look amazing. Big mistake, Lamar ... big mistake.