The act of a man ejaculating into the batter of a muffin mix then pooping into the batter making the poop looking like chocolate chips then bake the muffin then ejaculating into the icing spreading onto the muffin. Then they present it to an unfavorable person or animal.
Well you can have one of my mammy's jizz muffins you son of a batch of cookies!
similar to fuck off, but can be said in public places or around a younger audience. Also, must be done with a jacking off hand motion followed by a throwing motion, as if to throw the cum at the person you're telling to jizz off