Why does my roommates' boyfriend (27 years old) have a security pillow?
He still lives with his parents, and must have his pillow with him whenever he travels. It doesn’t matter if he’s on vacation in Europe, or sleeping over with his girlfriend. He completely freaks out if he doesn’t have his dingy pillow to rest his head on. There must be a psychological reason behind this. Can anyone shed some light on the matter?

He may have issues with growing up you know.
If he still lives with his parents, he probably always wants it to be this way.
So even when he goes somewhere else, he likes the feeling of the security of that house and his parents.
separation anxiety most likely he probably doesnt feel like he can live alone without his parents who have been helping him his whole life talk to him or have your roommate talk to him or have him talk to a pro
I would say it’s the same reason a child has a teddy bear: it makes them feel safe. His security pillow is something that makes him feel comfortable anywhere, regardless of the fact that he is twenty-seven and at an age when most people have abandoned objects like this. Or maybe he’s just gotten the pillow worn in just right, so that it’s perfectly fit to his head.
It is a ritual with him and brings him comfort.
I must say, that is the first time I’ve heard of that for his age. Is he very clingy to his Mom?
I don’t know,. but are you a female,. and are you hot,. maybe you could be my girlfriend,. ha,. ha,. just kidding,. I’m just joking,.