When you're doing doggystyle and spit on both of your index fingers and then proceed to stick them in your partners ears and twist; delivering a potent wet willy and shocking them into tightening their vagina/anus at the last minute before you ejaculate. Similar in function to a donkey punch although less violent.
Best used right before you finish and on considerably dorky individuals.
An alternative method is to use your fingers in a double fish hook technique to use your partners own spit.
That girl Brooke from school is such a dork, she wanted to smash last night so I hit her with the Dorkwad Willy Gripper.
A shit so big you have to grab the sides of the toilet to push it out.
Mike: Dude, are you okay?
Ed: Yeah, that bastard was so big, and wasn’t coming out, I had to hold on for dear life just to give birth to that monstrosity.
Mike: Oh, you experienced a seat gripper!!
Ed: I see you speak from experience.
When a gay man lets one use his butthole, and grabs one's balls with his hand as they do so.
My hookup from Tinder last night gave me a Wisconsin gripper... I don't think I've ever done that before!