How to make a perfect fluffy bed 

Are the mattress toppers foam or??? Brand? Source? Got a peek at them before you put in the fitted sheet. Thanks!

What if you have a king duvet? There isn’t a bigger insert than king. So how do you make king size fluffy? Add and extra one?

If you use a larger insert wouldn't it bunch up and create unsightly lumps and bumps?

Where do you get that duvet? Love it!