It is also a common word for the sound *smack* or similar, which is why in some "translated" games when the P in V action is happening the text goes "Bread BREAD! BREAD! bread bread BREAD!".Pan is bread in Japanese.
But Pan can also be an abbreviation of punch.
You know One Punch Man?
In Japanese it's Wan Pan Man.
So Face Pan (bread) and belly pan would be face punch and belly punch.
Long story short, it's a translation error.
They are in fact not making bread but getting a good pounding.
But lets not forget the no-pan either, the Japanese really likes their bread!