A very simple phrase with simple construction "clop" being the female genitalia and chops being a substitution for the word "mouth" or "cheeks" and can also be known as a handy punching area of one's face, for example -
"Hey phil, You're going the right way for a slap round the chops"
Usually sex obsessive men are known for performing this act which could lead to their friends and others handing them the title of "clop chops" Also those who enjoy to have the nose buried in a females ring piece which would usually result in ones chops being positioned closely to a woman's "clop"
"Shall we call Clop Chops? I haven't heard from him all day!"
"he's probably got some mucky bird sat on his face"