YOU SAID:

my muscles, my muscles, involuntarily flex

INTO JAPANESE

私の筋肉、私の筋肉、思わず屈曲する

BACK INTO ENGLISH

My muscles, my muscles, flexing involuntarily

INTO JAPANESE

私の筋肉、私の筋肉、思わず屈曲する

BACK INTO ENGLISH

My muscles, my muscles, flexing involuntarily