What Does the “Appearance of Fatigue from Staring” of the Tathāgatagarbha Mentioned in the Śūraṅgama Sūtra Mean?

The mark of heaviness/oppression (dauṣṭhulya-lakṣaṇa) of tathāgatagarbha's tactile contact is caused by the manas. The tathāgatagarbha itself, as the substance of tathāgatagarbha, has no oppressed contact or mark of oppressed contact, because it has no mental engagement toward the dharmas of the three realms. The tathāgatagarbha, whose mind-nature is quiescent and extinguished, ceaselessly gives rise to various dharmas following the manas's continuous grasping, and has no choice but to use the eyes to see forms, the ears to hear sounds, the nose to smell scents, the tongue to know tastes, the body to feel tangibles, and the mind consciousness to know dharmas. In this way, the mark of oppressed contact of the six sense bases (ṣaḍāyatana) appears. 

If the manas does not grasp at the various dharmas, the tathāgatagarbha abides in quiescence and extinction, does not give rise to the various dharmas, and does not produce these functions and activities of the six sense bases. False dharmas do not arise, and the tathāgatagarbha abides in truth, unmoving, wondrously profound and tranquil. Originally, the tathāgatagarbha gives rise to no dharmas at all and is unmoving with respect to all dharmas; but when karmic seeds mature, conditioned by causes, there is false activity, and the various dharmas inevitably must be born. Once the various dharmas are born, that is oppressed contact, being forced by the manas; yet the tathāgatagarbha has no thought or notion of being forced, and does not even know it is being forced—it merely acts in accordance with conditions, spontaneously, without entertaining any other thought.