3D touch has been introduced with iPhone 6s Plus. There are two behaviors added with this new interface layer: Peek and Pop.

Peek and Pop in a nutshell

Peek - Press hard

Pop - Press really hard

Checking for 3D support

You should check if the device has a 3D touch support. You can do this by checking the value of forceTouchCapability property of a UITraitCollection object. UITraitCollection describes the iOS interface environment for your app.

if (traitCollection.forceTouchCapability == .Available) {    
    registerForPreviewingWithDelegate(self, sourceView: view)
}

Implementing the delegate

You need to implement the two methods of UIViewControllerPreviewingDelegate in your class. One of the methods is for peek and the other one is for pop behavior.

The method to be implemented for the peek is previewingContext.

func previewingContext(previewingContext: UIViewControllerPreviewing, viewControllerForLocation location: CGPoint) -> UIViewController? {
    
    guard let indexPath = self.tableView.indexPathForRowAtPoint(location), cell = self.tableView.cellForRowAtIndexPath(indexPath) as? <YourTableViewCell> else {
        return nil
    }
    
    guard let datailVC = storyboard?.instantiateViewControllerWithIdentifier("<YourViewControllerIdentifier>") as? <YourViewController> else {
        return nil
    }

    datailVC.peekActive = true
    previewingContext.sourceRect = cell.frame

    // Do the stuff
    
    return datailVC

}

The method to be implemented for the pop is previewingContext. :)

func previewingContext(previewingContext: UIViewControllerPreviewing, commitViewController viewControllerToCommit: UIViewController) {

    let balanceViewController = viewControllerToCommit as! <YourViewController>

    // Do the stuff

    navigationController?.pushViewController(balanceViewController, animated: true)

}

As you can see they are overloaded methods. You can use 3D touch in any way implementing these methods.

Objective-C

//Checking for 3-D Touch availability
if ([self.traitCollection respondsToSelector:@selector(forceTouchCapability)] &&
        (self.traitCollection.forceTouchCapability == UIForceTouchCapabilityAvailable))
    {
        [self registerForPreviewingWithDelegate:self sourceView:self.view];
    }
//Peek
- (UIViewController *)previewingContext:(id<UIViewControllerPreviewing>)previewingContext
              viewControllerForLocation:(CGPoint)location {

    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];
    Country *country = [self countryForIndexPath:indexPath];
    if (country) {
        CountryCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
        if (cell) {
            previewingContext.sourceRect = cell.frame;
            UINavigationController *navController = [self.storyboard instantiateViewControllerWithIdentifier:@"UYLCountryNavController"];
            [self configureNavigationController:navController withCountry:country];
            return navController;
        }
    }
    return nil;
}
//Pop
- (void)previewingContext:(id<UIViewControllerPreviewing>)previewingContext commitViewController:(UIViewController *)viewControllerToCommit {
    
    [self showDetailViewController:viewControllerToCommit sender:self];
}

Objective-C

//Checking for 3-D Touch availability
if ([self.traitCollection respondsToSelector:@selector(forceTouchCapability)] &&
        (self.traitCollection.forceTouchCapability == UIForceTouchCapabilityAvailable))
    {
        [self registerForPreviewingWithDelegate:self sourceView:self.view];
    }
//Peek
- (UIViewController *)previewingContext:(id<UIViewControllerPreviewing>)previewingContext
              viewControllerForLocation:(CGPoint)location {

    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];
    Country *country = [self countryForIndexPath:indexPath];
    if (country) {
        CountryCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
        if (cell) {
            previewingContext.sourceRect = cell.frame;
            UINavigationController *navController = [self.storyboard instantiateViewControllerWithIdentifier:@"UYLCountryNavController"];
            [self configureNavigationController:navController withCountry:country];
            return navController;
        }
    }
    return nil;
}
//Pop
- (void)previewingContext:(id<UIViewControllerPreviewing>)previewingContext commitViewController:(UIViewController *)viewControllerToCommit {
    
    [self showDetailViewController:viewControllerToCommit sender:self];
}