Is there a way to silence incoming calls/texts?

[J0LL3Y]

I have cool ringtones that i like, but sometimes out in public i want to silence incoming calls/text fairly quickly by pressing one of the outside buttons, rather then unlocking the screen and either hitting answer or having to scroll the top part down to silence it. I've searched all throughout the internet trying to find ways to do it, but their either for other phones or just no answer. I've also tried hitting the volume buttons a few times but that never seems to work. Didn't know if i had to set it in the settings or download something. So i was just wondering if anybody had any ideas as to how i can do this. Thanks!