My dog just loves the heating pad. He'd sit on it all day if I left it on for him!
I keep my house at a warm 68-70 degrees (f), but even then he'll still curl up on the heating pad.
Is it OK for my dog to spend a lot of time on the heating pad?
Just put a towel or blanket over it, just like you would with a human and a heating pad. Don't forget to turn it off at night.
My dog also likes to be warm, and it's true that your pet is likely to move out of the area if he/she is too hot. I'd keep an eye on the pad to be sure there's no chance of burns (keep a blanket between) and occasionally rotate a night or two without the pad.
It's quite possible that your dog has become accustomed more to the area the mat is kept and prefers to sleep in that area, or enjoys that the fabric holds some of his/her scent.
I see not harm in a pup who enjoys tropical temperatures, so long as they have access to water and the pad is used with safety in mind :)
I agree with previous answers. As long as you can keep an eye on him and there's a blanket over it, he'll move if he gets too hot.
Yes just make sure it's covered with a blanket that was it's not hot to skin contact