coneheading 

Coneheading is a sexual act that involves a male (or female) strapping a strap-on dildo around their head and using it to penetrate their male (or female) partner.

"man, I was so drunk I couldn't get it up last night, but she had a strap on so we were coneheading for hours!"

coneheading by matrix_sage November 24, 2015

cockheading 

being stupid; showing stupidity; displaying lack of intelligence

So many definitions on Urban Dictionary are prime examples of cockheading.

cockheading by yorrick hunt June 2, 2008

Boneheading

People who jump in front of, or hang out behind people who are being filmed having a photo taken off.
They often wave to get on television.

"Check out those boneheads on the news"
"Someone is boneheading in this photo"

When news reporters are on the streets, people try to get on camera and "bonehead" by waving to the camera.

Boneheading by mrmooz June 22, 2007