As much as I hate to agree with a cat, it has to be under. Time was it didn’t matter, but since they made the tube bigger to sell you less without you realizing it (sometime since I was a teenager), the larger tube allows the roll to shift when you pull. With over & a full roll, when you pull it tends to slide back against the wall, leading to a one-sheet-tear-off tragedy; with under it slides away from the wall for a free, unencumbered unfurl, and all is groovy. It’s simple logic, folks.
As much as I hate to agree with a cat, it has to be under. Time was it didn’t matter, but since they made the tube bigger to sell you less without you realizing it (sometime since I was a teenager), the larger tube allows the roll to shift when you pull. With over & a full roll, when you pull it tends to slide back against the wall, leading to a one-sheet-tear-off tragedy; with under it slides away from the wall for a free, unencumbered unfurl, and all is groovy. It’s simple logic, folks.