As always there is something in german to respond to this (especially to this thumbnail):

„Du hast ein Gesicht wie ein Paar Latschen: Reintreten und wohlfühlen!“

Roughly translated to:

‚You have a face like a pair of slippers: step in and feel comfortable!‘ but with „reintreten“, here: ‚step in‘, primeraly meaning ‚to kick in‘.

Have fun with this random knowledge, copyright by K.I.Z., „Der durch die Scheibeboxxxer“.