One gesture, two opposite meanings
Few bearded dragon signals cause more confusion than the slow eye-close. Owners want it to mean their dragon is blissful, and sometimes it does: a dragon who is warm, settled, and enjoying gentle contact along his jaw or back may let his eyelids sink shut the way a cat does in a trusted lap. But bearded dragons also close their eyes to shut out a stimulus they cannot escape. A dragon being stroked in a way he dislikes, held when he wants down, or pestered by a hand that keeps coming cannot always walk away, so he does the next best thing and closes the world out. The eye-close itself is identical. The meaning lives everywhere else in his body.
Reading the rest of the body for the real answer
Start with the beard: pale and relaxed points to contentment, while a darkening beard alongside closed eyes points to stress. Then feel for muscle tone through your hand. A content dragon stays soft and heavy, breathing slow and even, sometimes leaning his head or body gently into the stroke. An uncomfortable dragon goes stiff, holds his breath in shallow bursts, twists his head away from the touch, or goes suddenly and unnaturally still. The pause test settles most arguments: stop stroking and wait. The content dragon frequently opens his eyes, looks around, and remains where he is. The one who was enduring it uses the break to relocate, shake off, or turn his back.
Where and how you stroke changes the message
Touch lands differently depending on where it goes. Use slow strokes along the jaw, the sides of the beard, and down the back rather than anything coming from above the head, where a descending hand echoes a predator and can trigger the eye on top of the head to stay firmly open and watching. Repeated patting on the top of the head, stroking against the scales, or continuing for long stretches after the first signs of stiffness all push the gesture from pleasure toward shutdown. Short sessions with pauses built in give the dragon repeated chances to tell you which version you are getting, and to opt back in by staying put.
Responding to what he is actually saying
When the reading is contentment, keep doing exactly what you were doing, at the same pace and pressure, and let the session end while he is still enjoying it. When the reading is shutdown, stop, set him somewhere he can walk away under his own power, and change one variable next time: a different spot, a lighter touch, a shorter session, or simply letting him sit on your hand untouched. Over a few weeks, you can learn your own dragon's personal tells, because individuals differ. When a few sessions still leave the reading unclear, put a follow-up question to KinsLe's Kinny; he answers using the KinsLe Answers library.