TapTapPass - Gesture-based Passcode Toggle for iOS 6
TapTapPass is a unique gesture based toggle for enabling and disabling your passcode lock, developed by bd452.
Once you've set up your gesture for the toggle, you can begin your action and your device will lock thus enabling the Passcode Lock.
From this point on the passcode will stay enabled until. Once you unlock the device with your passcode, the passcode feature will automatically be turned off, at which point you can either leave it off or you can use the gesture you created to enable the passcode once again. If you do not wish to activate the passcode, you can use the standard sleep button to do a standard, no-password lock.
This can come in handy when you really only want to lock your phone when your out in public. This should save you some time in the long-run if you only need your device passcode enabled for certain time frames.
You can find TapTapPass on Cydia for free.