How To Make Mattress Softer. Because memory foam responds to external temperatures a warm room will make it softer and a cold room will make it harder. Also rotating your mattress on the same side can be priceless.
This will involve walking on the mattress several times a day to loosen it. Rotate and flip it if your mattress can be rotated or flipped this option might provide some relief. You should do this every so often at least twice a year like the tires on your car need to be rotated for consistency so does the wear on your mattress.
If you have a regular mattress using a box spring support may help the mattress feel softer.
Adjusting the thermostat may help make your bed firmer. For example if you have a 100 memory foam mattress it tends to become softer when your room is warm which is why the softness bugs you. Rotate and flip it if your mattress can be rotated or flipped this option might provide some relief. Avoid softer foams and fibers however.