Tyrese put the pressure on Chris, saying ... "There is no joke you can crack to ever change the way we all feel." 50 Cent similarly encouraged him to quit.
Chris is in a tough spot -- enough people, including Jada Pinkett Smith, Spike Lee and Snoop Dogg ... have blasted the Academy's lack of diversity. So, it's obvious he'll have to address the matter during the Oscars broadcast.
But Tyrese's point -- this is one situation where Rock's comedic skills won't be appropriate. So far, Rock's standing firm.