fejéssel
fejéssel is a Hungarian word, the instrumental singular form of the noun fej, which means head. As an instrumental case, it indicates the instrument or means by which an action is performed, or the accompaniment to an action. Therefore, "fejéssel" translates to "with his/her/its head" or "by means of his/her/its head".
This grammatical construction is used in various contexts. For example, someone might be described as pushing