How do I dual cast spells?

[Hydeskinner60]

Can anybody answer this question? How do I dual cast to enhance the flames spell? I have tried everything I can think of to make it work but I can't combine the 2 flame spells together to make 1 stronger one. I want to apply dual casting to other spells also. Below is what I have done to try and accomplish this.

I am a level 28

1) I have used my perk points to get Novice Destruction and Destruction Dual Casting (so both have turned blue to orange)

2) Both flames spells are on both hands showing LR

3) When trying to dual cast I press LMB and RMB down at the same time. When I do this all I get is 2 separate flames

Please, Please somebody tell me what I am doing wrong and how to do this correctly.

 

I have tried this unmodded and modded both failed.