I do a lot of double diapering and believe me, there's a right way and a wrong way. Even though my outer diaper is a cloth pull-up the principle remains the same. NEVER SLIT THE INNER DIAPER. As it gets wet and the polymer begins to swell, it will ooze out and ruin the diaper and make a mess. There is a tool available on Amazon called a Wartenberg Pinwheel. My understanding is that it is first a medical device used to test sensation. Second, the bondage scene uses it to inflick some level of pain (watch your safe words) Third, it's used to puncture a bunch of holes in the plastic (or cloth -works with either they say) cover of the inner disposable. It looks like a sturdy steel handle with a small roller on the end. The roller has needle like spikes that puncture the plastic shell allowing flow through of pee while keeping the integrity of the inner diaper intact. I used to use a safety pin but that takes to long. It'a only around $7.00 and mine has really held up well. I like to use a cloth diaper as my outer diaper so when it gets wet I can change it and the inner disposable can be kept on. I just put on a dry pull-up cloth diaper, replace the plastic pants and I'm good to go. I use the pull-up cloth diaper when at home or if I won't be out too long. If I'm going to be out most of the day I usually opt for a good quality velcro closure diaper because it can be changed without removing all my clothes.I detest the nightmare of cleaning up a poopy diaper so my inner disposable stays on until I'm home and a proper clean-up (with a good shower) can be dune at my convenience. not only that, it saves me from going through a ton of expensive diapers. I use the confidry 24/7 disposable, in my opinion a superior diaper. Great quality plastic shell, unbelievable capacity for wetting and BM's.I need to wear virtually 24/7 and I've found this combination of double diaper a top performer. If you're just a recreational user it's still a great way to get that flow through and extra absorbancy, extending the wear time. Check it out at Amazon. You can also see it at wearing clouds.com.