Backpfeifengesicht
tʃaɪniːzle̞tə ɽi tä kɯᵝ nä ɽɯᵝ jo̞ ɯᵝ nä tʃaɪniːzle̞tə ɛn eɪ dʒiː juː ɑː aɪ tiː eɪ keɪ juː ɛn eɪ ɑː juː waɪ əʊmakɹɒn ɛn eɪ keɪ eɪ əʊ eɪ ɛf eɪ siː iː tiː eɪtʃ eɪ tiː ɛm eɪ keɪ iː ɛs waɪ əʊ juː dʌbəljuː eɪ ɛn tiː tiː əʊ eɪtʃ aɪ tiː aɪ tiː biː juː tiː dʌbəljuː aɪ tiː eɪtʃ eɪ ɛm əʊ ɑː iː eɪtʃ juː ɛm əʊ ɑː əʊ juː ɛs eɪ ɛn diː iː ɛks eɪ dʒiː dʒiː iː ɑː eɪ tiː iː diː siː əʊ ɛn ɛn əʊ tiː eɪ tiː aɪ əʊ ɛn
In Japanese 殴りたくなるような顔 (Naguritaku naru yō na kao – a face that makes you want to hit it), but with a more humorous and exaggerated connotation.
A face that looks like it deserves a slap.
Example
"Der Typ hat wirklich ein Backpfeifengesicht!"