pack fudge or pack your bags
A harsh choice between getting butt-fucked or getting tossed out, because you're not in the mood for their nonsense anymore.
Bro: You either take it up the rear or I'm leaving. No more of this back-and-forth nonsense.
Girl: I'm done. You're either taking it up the rear or I'm moving out.
He: Pack fudge or pack your bags, I'm not your doormat anymore.