That's indeed a typical thing for him to do (but with closed eyes not so often, but just hiding and resting in this position, he's doing this often when he has enough of basking).
Took him out today for a while, and showed him over Zoom in a work meeting. People were surprised that such a spiky guy lets himself being pet

During the last weeks, Taco learned that he can influence where he gets pet not only negative (= closing his eyes), but also positively by presenting that body part. I love to see how he finds out more about how humans work

He also, over time, has learned the same for being taken out. For a long time, he was like "not wanting to come out = go away, wanting to come out = go up on higher structures, hold still and be picked up". He's now like when he's sometimes on the floor of the enclosure but wants to come out, when I put my arm in and he sees I just can't reach him (I just can't touch the bottom of the enclosure with my hand, it's almost 80 cm high and opens from the top, and I'm really not tall), he walks over, jumps the remaining centimeters up and climbs.
Yesterday I saw him digging out his cave a bit more, I guess the sand had shifted a bit from constant use, and was not well enough "bed-shaped" anymore. He always likes to rest his head on something that's a bit higher.
When he was younger, he more preferred to do "nose down", face firmly pressed between e.g. two stones, or into any other triangular gap. Now it's more body wiggling under something and resting his head higher on something. I think this change in behavior has something to do with him now being a big, adult dragon he has instinctively less predators to fear, so he doesn't have to squeeze in that tight.
I have seen that my dragon likes some light but steady pressure from above, like with my hand, or him wiggling under something (no worry, everything is secured very well or is light!). Especially when resting, sleeping.