口の端からささやく whisper out of the corner of one's mouth

口の端から血を流す drip blood from the corner of one's mouth

口の端から言う say out of the corner of one's mouth

口の端から吐き出すように言う hiss out of the corner of one's mouth

口の端っこでブツブツと文句を言う mutter out of the side of one's mouth

口の端に around one's mouth

口の端に唾をためる gather [collect] spittle at the corner of one's mouth