Instead of getting frustrated over the refractory period which to be honest you probably can’t do much about, maybe you should instead plan your time better to suit how your diaper fetish works for you.
Perhaps devoting a whole day to diapers isn’t such a great idea if you know once you’ve blown your beans it’s all over, you might as well devote a smaller amount of time to diapers and have other, none ABDL activities lined up once you’re done.