The verb is properly κορωνιάω ; it appears next to γαυριάω in e.g. Dio Chrysostom 78.33. Verb also in epsilon 540 (ἐκορωνία ), where it is likewise glossed with γαυριάω ; κορονιῶν is also so glossed in Hesychius.
Of the forms, the present participle κορονιῶν (for the Suda's κορονῶν ) occurs in Greek Anthology 9.777.1-2: "see how the horse, in art of bronze cunning, arches its neck". On ἐκορώνα = ἐκορωνία see epsilon 540.