A sexual act that involves the recipient cupping their hands around their eyes mimicking binoculars at which point their partner spray farts into their face. The hand placement allows for the funneling of the plume of fecal material onto the eye. The result is a distinct distribution of shit which resembles spectacles.
Erich: "Check out the gait on that girl"
Perkins: "I'd like her to shit on my eyes"
Erich: "Rusty Binoculars??"
Perkins: "Hell yeah, a concentrated burst."