It seems these guys have found a way to do this for iOS 9 for phones with the Taptic Engine (including the iPhone 6S). http://unifiedsense.com/development/using-taptic-engine-on-ios.html I'm not sure if this applies to iOS 8 or other phones. They essentially retrieved the Taptic Engine interface from the UIDevice and called actuateFeedback with an integer matching Peek or Pop.
Unfortunately, these applications are likely to be rejected by the App Store, if that is your intention.
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