[razorz]

Everytime your main hand hits, you have a chance to dual wield and double attack. This is why there is a "skill" for dual wielding, otherwise you would just train 1 point and it would work. This is also why you dont always swing your offhand, even if it only has an 18 delay while your main has a 22 delay.

It's probably reasonably simple to recode that part of the emu mechanics, if they wanted to do so. It's similar to a dice roll:

Main hand swings roll dice based on dual wield skill, high enough dice roll, offhand swings, another dice roll is done to check if main or offhand are going to double attack as well.