Well, both, kinda.

Splooting either means relaxation or they are hot. But hedgehogs are often WILDLY anxious creatures. You hedgehog will make it very clear when its uncomfortable. The more they "pop", " hsssffff", deploy their quills and curl up the more anxious they are. Though they do this quite often.

Hedgehogs love to burrow. So this is highly likely to be it relaxing in a spot its comfy. Flat quills, exposed legs, etc. Big comf. #hedgehogs