Michael Bisping says there are two little things holding up his superfight with Georges St-Pierre ... GSP's testicles.

The reigning UFC middleweight champ tells TMZ Sports he's ready to fight Georges RIGHT NOW -- but St-Pierre is holding up the process.

"I think he's waiting for his balls to grow," Bisping said ... "I think he's doing some bicep curls, taking some protein shakes and then when he's big enough, then maybe we can do the fight."

Meantime, Bisping's now in Thailand to shoot the action movie "Triple Threat" with Michael Jai White and Tony Jaa

As for allegations Bisping's ducking other fighters like Yoel Romero and Jacare Souza -- The Count has some strong words for them too.