This is where you move from co-sleeping on the same surface, to co-sleeping on separate surfaces, and then gradually move your child’s mattress further away until you feel both you, and your child, are ready for the move to separate rooms.
Please add your experiences with this approach in the comments below. Please provide the age of your child when you tried it. Let us know how long you tried it it for. If it helped, please share the effects you saw. If it didn’t help, why do you think it didn’t work in your case?