Foam rollers have many uses and one of the most common is as a fulcrum to stretch the upper back into extension (backbend). The thoracic spine (upper back) is notoriously difficult and fickle to work with. I have found for a many people a foam roller can be quite aggressive and uncomfortable, often defeating the purpose of the intervention as the person is either uncomfortable or unable to relax.
Recently I have been using a medicine ball for the same purpose. See below:
With a medicine ball there is a larger surface area, so the pressure is not acutely focused on any one particular area, and allows for a greater exploration of movement in various planes. The ball also has a quality of soft yet firm texture and feels nice as it forms to your body.
If you have been using a foam roller for a similar purpose, give a medicine ball a try and let me know what you think in the comments!