The cartoon on the obverse of the card is a humorous depiction of the kind of scene that every soldier would love to experience (but never will).
The smiling SNCO (instantly recognizable as a Hauptfeldwebel (Spieß) by the notebook tucked into his field blouse and the twin Tresse rings on the sleeves) enters the privates' bunk room, saying...:
"Darf ich zum Dienst bitten, meine Herren!" ["May I ask you out for duty, gentlemen!"]
...to which the soldiers reply:
"M.w. / Machen wir!" ["W.d. / Will do!"]
"Umgänglicher Mann, der Hauptfeldwebel!" ["Affable man, that Hauptfeldwebel!"]
"Ist ja ein gemütlicher Laden hier!" ["Now this is one easy-going place here!"]
The card was written by a private named Ludwig Klein and sent to his son Eugen back home at Hauenstein in the Palatinate.
The text on the reverse says:
zu Deinem Geburtstag sendet
Dir recht herzliche Grüße Dein
Hoffe daß Du recht brav bist u. [= und]
der Mutter etwas mithilfst"
cordial greetings for your birthday
sent by your
Hope that you are good and
that you help mother a little"
The word next to where the stamp would be is "Feldpost". ["Field post"].