To be in an extremely foul mood, akin to having your pants full of shit similar to an infant with a shit laden diaper.
Jeremy: STFU, I'm sick of listening to your crap.
Mike: You're grumpy poo poo pants because your mom didn't blow you last night!
Mike: You're grumpy poo poo pants because your mom didn't blow you last night!
by CyberWank September 2, 2010
Get the grumpy poo poo pantsmug.