Remember Bendgate, where people's iPhone 6 Pluses were warping in their pockets? It seems Apple really have learned their lesson and implemented sufficient measures to ensure it doesn't happen again.
Christian, a YouTuber from Australian website FoneFox, was one of the first people in the world to get his hands on an iPhone 6s Plus, and promptly proceeded to abuse it to see if it would bend like its predecessor.
Not this time
Thankfully, Apple's equipped the iPhone 6s Plus with a reinforced body thanks to its new 7000 Series aluminium alloy that incorporates Zinc, making it their strongest chassis ever. When coupled with a new molecularly stronger glass made to be the most durable in the smartphone industry, what you've got is the toughest iPhone ever.
From the video, you'll see that Christian puts considerable effort into bending the phone, but to no avail. In fact, the phone flexed with the pressure, and promptly reverted to its original shape right after it was released. The only time the phone did bend was when two grown men tried with all their might, but that's hardly likely to happen in the real world. Unless you've got very rich and very bored friends, that is.