Anal ducking
The act of quacking with each thrust of a penis, or other phallic object, into someone's rectum.
I dodged a donkey kick shortly after I started anal ducking her.
Anal Duck Sex
When two partners engage in anal sex while the penetrating partner rotates clockwise during penetration - similar to how a ducks penis is corkscrewed.
Man, I had anal duck sex last night. Shit was dizzying!