iOS has two different types of volume
modes that is ringer volume and media volume that you have not notice yet, where
the ringer volume is used to adjust the sound of ring tones, text
tones and notification tones while the media volume is usually used to controls
 the volume of songs, videos, in-game
music etc.
SwitchHUD allows you to quickly and easily toggle between ringer and general volume by which you can know exactly what volume you’re changing.
So whenever you toggle volume button it always makes as
default to ringer volume and it will not change to volume ringer unless we play
the music, videos etc which is quite uneasy to switch your volume with this
process.
But if you want to quickly switch between ringer and general volume quickly without confusion then there is a tweak
called SwitchHUD in Cydia which allows you to quickly and easily toggle between
ringer and general volume by which you can know exactly what volume you’re
changing.
After installing SwitchHUD you can have
option to configure in the tweak preferences from the settings app where you
can assign Activator for the tweak.
SwitchHUD is available in Cydia via BigBoss
Repo for free and is compatible with iOS devices running iOS 8 and iOS 9.
How to quickly switch between Ringer and Volume on iPhone/iPad
  • Simply open Cydia – Tap on Search and type the name of the Cydia
    tweak SwitchHUD and Tap install. 
  • Respring your device because the tweaks may not work properly if
    you do not respring or reboot your device.
  • Now Go to Settings>Scroll down and Select SwitchHUD
  •  In the tweak preferences assign Activator gesture you want.
That’s it. You can now quickly toggle or switch between ringer and volume on your iPhone and iPad.

If you are not yet jailbroken then
follow this step by step guide on How to jailbreak iOS 9.0.2 using Pangu?