ive had my iPod touch 5th Gen since the week of release, over 2 years now. it use to be in a case but about a year ago i got bored and just used it without anything protecting it. then when i saw the iPhone 6+ would bend i looked at my iPod from an angle to tell if the edge was bent, it was slightly curved about 1-2mm over the whole device, i hadn't noticed because its such a small curve. also i noticed that the device's four corners touched a flat surface at the same time, even though it has a sticky out camera so it should rock slightly if it was straight.
these iPods are made from aluminium which is a soft metal, having a long thin piece of soft metal and putting it in tight pockets is a recipe for disaster!! 🙂 i did put my iPod in back pocket sometimes and it has been dropped a few times so its a tough thing. what i would say is that these devices have a very large length to thickness ratio, so they act as a lever upon themselves. if you try and snap a 2cm small stick 5mm wide its hard but if you've got a 50cm 5mm thick stick its easy. if you're an iPod touch user be aware of the fragility of the device, i was not and its warped. i bent it back now and its fine. but DO NOT try this, if you press on the back panel or screen hard you WILL smash or break it. the battery is very fragile and same for the LCD display. And if you try and bend it back too hard the edges of iPod will fold in and smash the display- i heard this happens with iPhone 6+ too.
Bit of advice for all users, don't try and bend it or sit on it, because it probably will get warped, or even smash, as the display is glass and glass doesn't bend :]