The affix ic comes after a bahuvrīhi samāsa when the compound denotes the reciprocity of an action.,
The compound denoting reciprocity of action is formed by 2.2.27. Thus केशाकेशि = केशेषु केशेषु गृहीत्वा इदं युद्धं प्रवृत्तं ॥ So also कचाकचि, मुसलामुसलि, दण्डादण्डि ॥ The affix इच् forms also avyayibhava compounds, as it occurs in the list of तिष्ठद्गु words 2.1.17.,