Hello,
I found this lizard tutorial and was very anxious to try this out, however I am stuck at step 2!!.. I think I am just too stupid… =(
" Step 2) Extrude the backside of the box out five times into a “U” shape. )At this point we are already creating what will become the mouth loop.) "
I simply cannot get the V shape at the back without creating another face in between the mouth by extruding…
Please check the picture for the steps.
Please see the one I am having now…
You ended up with triangles on the sides. If you look closely at the original, those two pieces actually still have four edges on the side. Try this…
Extrude a short distance. Drag the bottom row of corner vertices down a little. Then drag the top corner vertices down and out as shown. The next shape should be similar. This gives you what will become a nice curve at the corner of the mouth.
Thanks!!.. You made it look so simple, and I am beginning to doubt my intelligence… 
At this rate I think I will be able to complete the lizard at year 2026 if without your help…
Nothing is simple till you know how 
The original post you’re copying was by Torq who seemed to have an uncanny knack of seeing loops before he even started modelling. He made it all look easy (look for his “better face tutorial” when you’re ready)
Just keep in mind that every new face you make in your model should have four edges - even if they sometimes look like triangles.