Drop food in his tank at least once a day. He'll get out of the water as often as he wants. And knows when it's time to get back in. I don't know what you mean exactly by 'stiffens' but check your lights, they might be a little too hot or bright for him. You can touch his shell, legs, tail, head, toes. Anywhere really. But like any other reptile go with the scales not against. You can also let him walk around the floor of your house/room. But always keep an eye out. They move surprisingly fast when they're out and about. But it's good for them to get out. And if they tip over and sit upside down, he won't die. But it does make it harder for him to breathe, so don't let him sit upside down for too long.