The affix śyan comes after the roots kuṣ 'to pull' and rañja 'to colour' in the reflexive voice, according to the opinion of Eastern Grammarians and these verbs take the affixes of parasmaipada ,
This debars the affix यक् and the Atmanepada terminations. As कुष्यति पादः स्वयमेव 'the foot draws up of itself'; रज्यति वस्त्रं स्वयमेव 'the cloth colours of itself'.
The phrase 'in the opinion of the Eastern' shows that it is an optional rule; so that we have also the forms कुष्यते and रज्यते.,