After jailbreaking your iPhone one of the first things you might have wanted to do is to customize your Notification Center. Unfortunately though, when you start tweaking your Notification Center you'll find that it will start becoming unresponsive and laggy. Especially when you are pulling down the Notification Center. The fix is really simple, but it's perhaps not what you were waiting to hear. Remove some of these customizations.
If you really want to narrow down your choices, you can navigate to Settings --> Notifications and start hiding some of the tweaks from your Notification Center. It could be that you tweaked your Notification Center to add in a few toggles or an extra button recently. Either one of these tweaks could be causing the issue, or perhaps even both. Just play around and hide some of the tweaks and narrow down your choices to find exactly which tweaks are the ones causing your Notification Center to become unresponsive.
That's unfortunately the only fix out there. If you know a better way please share it in the comments below.