hmm. when im handling my own they are always active, there is a time when they just sit there, yours is probably just chilling, you know. lol. maybe it feels that safe with you it may have fallen alseep, i usually just stroke mine and then they flicker their tongue, at the moment with my eldest, missy, as shes not very well, she dont move at all, not in the viv or in my hands, nor when i go to take her out her viv she still doenst flicker her tongue, so at the mo, im always poking her or stroking her to get her tongue flicking.
but i normally stare right up close at their eyes, coz brown eyed ones you can see their eyes move about and what they are looking at. if they are still but their eyes are moving i know they are chilling but if their eyes are not moving then i assume they are asleep.
hope this helps