Talk about hitting below the belt ...
UFC superstar Michael Bisping is ripping into Anderson Silva -- claiming the guy's history of PED usage left him with a wonky penis ... and Bisping's not afraid to mock him for it.
The two are set to face off at UFC Fight Night in England on Feb. 27th -- and even though Bisping says he believes Silva is clean for this fight, he thinks Silva had been cheating for years.
"He was using his entire career," Bisping says.
Check out the clip ... Bisping also predicts exactly when and how he plans to beat Silva.
BONUS -- we also asked Bisping how he felt about another high quality smack talker, Donald Trump. Ya gotta hear what he says about the presidential candidate.