I would really like to tuck my denim shirt into a pencil skirt. Problem is, the shirt is quite long and creates unsightly "bunching" or "VTL" (Visible Tucking Lines) under the skirt even when I pull it really taut underneath and make sure it lies flat. You can see the lines across my backside and it looks really off.

I know lots of you successfully tuck button down shirts and other tops into skirts and pants...what are your tips and tricks for creating a neat line doing this?