This is one of my favorite stretches and you can use a countertop, a table, a barre - anything that’s about the height of your hips! Whatever surface you use, it should be stable and secure enough to not move if you pull on it.
Just hold onto it with straight arms and step back until your body makes a 90 degree angle and your back is parallel to the floor. You should feel a great stretch across your back.
You can also take this into a tricep stretch by stepping closer and resting your elbows on the barre and bending your arms back over your body.