Dumber Than Dirt

A variation of "dumb as dirt" used in the graphic adventure video game Full Throttle developed by LucasArts.

Extremely stupid.

Likely conceived for its alliteration.

Ripburger, you're dumber than dirt!

Shoehorn

When you are super-wasted and have to lead your semi-flaccid penis into a vagina with your pointer and middle fingers just like a shoehorn would fit your foot into a shoe.

Tommy: Bro, I barely got it in. She was so fuckin' hot! She needed it, but I was shitfaced as usual.
Kevin: So, you shoehorn'd her?
Tommy: Yes
Kevin: Creepy, Well?
Tommy: Well, that got it started. Still didn't perform. But, at the end of the day I can still say I fucked her. So...
Kevin: So who was it?
Tommy: You're mom!