11 month old DS. When he's asleep he often sits up, he has done since he could at about 8 months, it can be once or several times in the evening or during a day nap. We cosleep at night and it happens more when he's on his own, but can happen even when I'm in bed with him.
He usually sits calmly, quietly and very sleepily with his hands in his lap. When one of us gets to him, he usually reaches his arms out for a quick cuddle, gets lain back down and then he'll go back to sleep. Sometimes he might want his back rubbed a little. He can lie down fine by himself when he's awake. I tried Google and it links sitting up to having night terrors. DH thinks I'm being too anxious again, says he just does it to get a cuddle if he feels lonely when he wakes up, but I'm worried now that he's having bad dreams and I'm not sure what to do about it. He's a happy little soul when he's awake.