首楞嚴義疏注經 7.189

7.189

由執著故一心趣境，濕煖之處與想相應，即便受生，故云煖成。翻覆亂想者，因即違心背信，翻覆任情，遂感類生，飛走不定。蔽尸，云軟肉，以其初受濕生，形尚柔軟，既不入胎，故無前位。

Because of grasping, they incline toward sensory objects with a single mind; wherever there is moisture and warmth, corresponding with their thought, they undergo birth immediately; hence it is said, 'formed with warmth.' As for 'chaotic thoughts of turning and overturning,' the cause is going against one's mind and betraying trust, turning and overturning according to whims, which consequently evokes birth into this class, flying and running restlessly. 'Peśī' means 'soft flesh'; because it first receives moisture-birth, its form is still soft; since it does not enter a womb, it lacks the previous stages.