It is helpful to use something thin like a credit card as a shoe horn here - while the back edge is still raised, insert a thin card between the edge of the drive and the foam block, then push the drive edge down and slip the card out. This will allow the end of the drive to sit flush against the block without any overlap or mashing of the block. It also eliminates the need to keep pressing or forcing the edge of the drive to fit.
It is helpful to use something thin like a credit card as a shoe horn here - while the back edge is still raised, insert a thin card between the edge of the drive and the foam block, then push the drive edge down and slip the card out. This will allow the end of the drive to sit flush against the block without any overlap or mashing of the block. It also eliminates the need to keep pressing or forcing the edge of the drive to fit.