I don't have twins, but my daughter was trained by 2. Seems it would be easier to train 2 of them with it sort of being a competition or fun sitting on the potty side by side. :) With my daughter I just cut back on liquids 3 hrs before bedtime except for sips...then later bought her some frilly panties..she didn't want to soil them so she went in the potty. I think with any child it is more about training yourself in the beginning to take them every hour or 2 (first thing in the morning, mid morn, before lunch, after lunch, before nap, after nap, before dinner, after din, before bed)until they get into the routine. Then they will get in the habit of going and at least try. Give lots of praise even for trying. After a while they will begin to recognize ther own body signals and notice the feeling they get when they need to go and they will aquaint it with the fact that when they get that feeling if they get on the potty, they can go. There is no rushing it, with some it just CLICKS faster and others take a bit longer to figure it out. Good luck! :)