The Armenian Sledgehammer 

While receiving head (preferably with your partner on all fours, not on knees), ball your hand into a tight fist and hit your them as hard as you can in the rectum, directly before ejaculating. Not only is this hilarious, it also feels great.

John: "How was last night with Tom?"
Kate: "It was great until Tom hit me with the Armenian Sledgehammer."
John: "Ooh... that sucks."
Kate: "I won't be able to sit right for a week."

The Armenian Sledgehammer by Aram A. April 2, 2008

The Puerto Rican Sledgehammer  

A highly complex sexual maneuver involving a crane, various engines, nautical equipment and fire. Its origin is unknown, and it has only been performed once in the history of mankind. While the exact procedure remains unclear, it continues to be recognized as one of the world's most dangerous sexual acts.

Kevin: Dude, Mike was the only one to perform the Puerto Rican sledgehammer and survive. He came out of it with just a broken wrist!
Max: Boobies!

The Puerto Rican Sledgehammer by SexSarge69 January 21, 2009

Sledgehammer to the coin machine 

When a sledgehammer is swung willy nilly like towards the genitals of another person.

"Hey did you hear about Wilcox? He took a sledgehammer to the coin machine."
"Really? He must have been in Florida."

Sledgehammer to the coin machine by The coin purse bandit May 18, 2022