To take a customary action to ward off some misfortune that is believed to be attracted by a presumptuous statement.
Hopefully; a self-directive to undertake the customary action to ward off bad luck.
To become apparent in an unwelcome way, to be forcibly imposed; to jut in, to intrude (on or into).
To impose (oneself) on others; to cut in.
To proffer (something) by force; to impose (something) on someone or into some area.