Yo Mama Climbs Mountain Dew

Alright, listen up, buttercup. This "yo mama" joke is all about saying someone's mom is dumb. In this case, she's so dumb she tried to climb a Mountain Dew, which is a soda. It's supposed to be ridiculous because Mountain Dew is a drink, not a mountain. You probably thought Mountain Dew was a real mountain, didn't you?