if you have a fire spell on each hand and hit both triggers at the same time, you get a more powerful version of that spell.


What happens if you have a spell in one hand and a sword in the other hand and hit both triggers?

you only get a better version if you have the perk.

Then you swing a sword while shooting magic.

It should be noted that the doublecast improvement requires a perk. Otherwise you're just casting two regular spells.