Who wore it better

A community for comic lovers who just want to get away from politics and gloom and doom.
Posting guidelines:

Who wore it better

I'm old. Can someone explain the joke? The best I can come up with ass shaking is called "throwing a grenade"?
"When a person hyper extends their back creating a moon shaped body and a large bubble butt"
https://www.urbandictionary.com/define.php?term=throw+it+back
Considering the firing lever is still there, im pretty sure the grenade hasn't been armed
The enemy just wanted a free show
"Damn, that's hot... And filled with shrapnel."