Awww...no need to explain, I know EXACTLY what you are trying to say.
As for Con and not having that "natural curiosity" I'd start by "hiding" a favorite treat inside a BIG cave made with your blanket and slowly make the "cave" smaller and deeper.
When I say BIG, let me try to explain, when you first pull up the blanket it should look like a wall with like an inset, so like a really shallow cave and put the treat or toy he might want to get there, at first he won't know he's going "inside" something, then as the days, weeks and months pass...you can make the cave deeper and smaller where he has to actually have the blanket touch his head and back when he goes in to get his treat and progress from there.
Franklin now just puts his head down and barges in the blankets making his own caves and tunnels. It's sooo funny to watch him dart in and out all over our bed.
Franklin is also a very good climber and it's his other favorite pass time, so I incorporated the blankets and being on his back into his love for climbing and being inside the "tunnels." I'd hold the blanket up high making like a big hill and he'd climb up the side of the hill...then when he'd be part way up, I'd start "dropping" the blanket and raise it up and drop it back down and raise it up...kind of like Franklin was on a bouncy ride...hahahaha...well, of course he thought that was the best, goofy bird...so then to get him more and more used to being on his back, when I'd lower the blanket I'd manipulate it so that he would "land" on his back holding onto the blanket, then I'd pick it back up and of course he'd still be holding onto the blanket, I'd pick up bottom of the "hill" of the blanket while he was trying to "climb to the top" so he'd be climbing on a "tight rope" upside down (his back facing the bed) and then I'd lower the blanket to the bed and pick it up and then eventually I'd leave the blanket down covering him while he was laying on his back, then he'd scoot out on his back. So funny to watch him. And I'd grandly praise him for showing me his new "trick" and then of course I just built on that.
He did naturally roll onto his back in the cage at the petstore, it's one of the reasons he sucked us into buying him! HAhahahahaa. So I knew he wasn't terrified of being on his back.
Anyway, as you can see, we use the blankets a lot when playing with Franklin and it's definitely helped in the "toweling" department. Now days, he never knows when he's being toweled. He just thinks we're playing.
Toni