relax into something
1. to sit or lie down in something, relaxing. I want to go home and relax into my easy chair. I relaxed into the reclining chair and was asleep in a few moments.
2. [for something that is tense] to assume a more relaxed shape or condition. His cramped muscle finally relaxed into a soft mass of tissue. As her tight neck relaxed into softness, her face brightened.