Mahomes admitted that he's not an MVP when it comes to changing his 6-month-old daughter Sterling's diaper ... but Coach Reid, who's a father of 5, is helpin' him out.

"I’ve gotten alright at changing diapers. I’m not the best. I’m not going to lie to everybody," the Kansas Chiefs QB said on "Good Morning Football."

"But, I think if you gave me the dummy baby and I could do it on paper, but as far as applying it to a moving baby that’s screaming a little bit, crying a little bit ... I crack a little bit under pressure."

This is coming from a Super Bowl champ who's always dodging pressure and ends up making insane plays that even has the defense impressed ... so it's SHOCKING to hear about the dude's vulnerability.

And, like football, changing diapers is not just a physical thing but a mental as well ... something Coach Reid taught the 25-year-old dad.

"You gotta have the right mentality going in. I think that’s the biggest thing he preaches to me," Mahomes said.

"You gotta have the right mindset going in and know that you might face some adversity when you’re there."

Mahomes also gives credit to his fiancée, Brittany Matthews ... saying she's "an amazing mom, who’s done great job at helping me out becoming a new dad."