New cat doesn't want to socialize
I got a second cat on June 1, Murphy. He is very affectionate with me, but since I already have a petite little Tortie at home (Nugget) who still hasn't completely accepted him (they will bump noses and even sleep on my bed together at night, on opposite sides, but then she also swats him when he comes too close), he spends most of his time under the guest bed, not even sleeping on it comfortably. Instead he plays limbo and squishes himself under the bed to sleep most of the day. He came from a loving shelter without cages, and is used to other cats, but still is very uncomfortable socializing with us out in the main part of the house. He is extremely friendly towards people.
I have closed off his room to force him out of there, and then find him laying on the bathroom floor instead of being out with us.
Does anyone have any suggestions on what to do next? He is a cute guy, but apparently shy. The shelter said that was his normal reaction to situations, but it's been almost a month and I can't get him to stay with us much more than when I first brought him home.
He is 3, Nugget is 4 if that makes any difference. She has only been with me since last August. He is at least twice her size. I am teaching him to become a cat (playing with toys, chasing fishing pole feathers, etc). He was found in a feral cat colony trying to survive, but acts anything BUT feral with people.