Only have flex disc and out of pads, flex disc randomly empties on me

How do I prevent these things from emptying on me? If I sneeze or cough they will empty. They will empty if I do nothing. They will empty if I laugh. I feel like I should just go back to pads by this point because I need to wear one anyways for these occasions. I am not in a position to get a smaller size, I need tips on how to make a potentially too large menstrual disc work until then.