Coprophagia and Pica
A lot of what puppies and dogs do is pretty gross to us humans. It's hard to believe that something so adorable and sweet can do some of the disgusting things they do at times - especially after you just let them lick on your face :"/ Though it can sometimes be a sign of illness or other issues, most coprophagia and pica is normal. You can go here to read some about it:
http://www.lucythewonderdog.com/eating-feces.html If you are not able to distract your pups to curtail the habit, you might ask your vet – or research online - about a nutritional product that you can give them to cause the feces to taste nasty to them.