We just started solid foods with my daughter.
I've discovered that when I feed her, I sub-consciously move my mouth to mimic the shape that I want her to make and my head towards what would be her angle of easiest spoon entry. Or when food is falling out, my lips move as if I was trying to catch it from falling out of my own mouth.
It's sort of like how some people move their whole body when playing video games to move or turn faster. Damn Mario Kart.