Peyton, Eli Go In-Depth About Butt Cheeks During 'MNF' ManningCast

Forget pigskins ... Monday night's "ManningCast" devolved into an in-depth chat about butt skins -- and the whole conversation between Peyton, Eli and comedian Nate Bargatze was hilarious!!!

The talk about NFL players' cakes went down while the trio was helping broadcast the "Monday Night Football" doubleheader involving the Titans vs. Dolphins and the Giants vs. Packers.

At one point during the 'Fins game, Tua Tagovailoa's starting center went out ... which led to Nate asking the two former quarterbacks about their familiarity with backup centers.

The Manning bros then revealed they don't love the situation -- insisting they don't want to get too cozy with too many sets of their teammates' butt cheeks.

"It's a comfort area," Eli said. "You don't want to go around that area with too many people."

Added Peyton, "You kind of want your hands to be for one set of butt cheeks, Nate. So, you kinda don't really want to share that with several. You try to stay loyal."

Nate -- who recently hosted "Saturday Night Live" -- didn't let the conversation die there, though ... 'cause he then just had to ask if the Mannings could identify their centers' asses even if they were blindfolded.

"I could for sure," Peyton said. "I knew Jeff Saturday's butt cheeks as well as anybody."

Peyton -- who played with Saturday on the Colts from 1999 to 2011 -- continued with his butt talk, adding, "You don't want to use blindfold and butt cheeks together very often ..." before Eli eventually put a stop to it.