How to deactivate Siri on Home Button

If you're regularly activating Siri just by sitting in a chair, you're putting your phone in the wrong pocket. And do spare us the bad language, please.

Go to setting, general, Siri, turn off Siri is the only way

I keep my phone in a pocket most of the time and have never once managed to accidentally activate Siri. So, yes, I'm serious. The only way I can see that happening is if you're putting the phone in a back pocket and sitting on it. Not a great idea, for all sorts of reasons. So there are available pockets whch are clearly the "wrong pocket" for keeping an iPhone.

1. Try a reset: Simultaneously hold down the Home and On buttons until the device shuts down. Ignore the off slider if it appears. Once shut down is complete, if it doesn't restart on it own, turn the device back on using the On button. In some cases it also helps to double click the Home button and close all apps BEFORE doing the reset.
2. Settings app > General > Siri > turn off.

1 Settings - General - Siri - Off

2) Settings - General - Keyboard - Dictation - Off

3) Settings - General - Restrictions - On - Enter Passcode - Siri & Dictation - Off

SORTED

Hello, there, harlaneyside. Your suggested settings seem reasonable, and are indeed the only ones I've been able to find on this website or anywhere else in my searches across the web. Much appreciated, and I'll keep looking. N.b., though, on both my iPad Mini and my iPhone 6+, both scrupulously maintained and at 9.0.2 (as of this post on 10/11/15), these settings changes seem not to suffice. If I hold down the Home button on either device, the device "obediently" (or, I would call it, "disobediently") blacks the screen and presents a wave form, waiting for my voice to suggest a request for help.

"Call me frustrated."

"Okay, you're Frustrated. How can I help you, Frustrated?"

Yeah, I thought it worked at first, but it doesn't; sorry. I now have an iPad with Smart Case and I can avoid using the home button by combining the Case's sleep-wake feature with a 'floating' on screen home button (available in Settings> General> Accessibility> Assistive Touch> On). So far, since I first turned on the iPad, I've only used the physical Home button once, to do a reset. As for the iPhone, well, at least I'm using it much less now, so Siri problem less hassle. I also use Assitive Touch on iPhone, but it can be a pain, 'cos of smaller screen.

Yep, smart cover for me, too. But I'm (for now) using the iPhone as much, for one thing the convenience of Apple Pay, and for another (since its screen is so big) the convenience of not needing the pad during long trips. (Heck, using Textastic, I can even maintain my websites ☺️)

Ah, well, "Siri, call me a taxi." "Okay, you're a taxi." "Siri, call out for a pizza." "Okay. YO! PIZZA!”

Go to "Touch ID & Code" and enter your passcode. Disable Siri Access for locked mode.

This was the only thing that worked for me. Completely insane design.