I had this vision in my head right after watching Toy Story of Terror for the first time.
The special was pretty intense and I'm sure some of those experiences have affected the toys following night(s).
While Jessie was being able to somewhat defeat her fears and managed to save not just herself but all the others, Buzz was trapped behind the glass. He had to watch Jessie being attacked by iguana, watch her struggle with it, then at the end watch her being sealed in a BOX to be sent god knows where and all of this time he was unable to help her. He couldn't protect her. And then there was a massive chance of losing her maybe forever...
These events most have been haunting him in his dreams. But when he suddenly wakes up from those nightmares Jessie is always there. She lets him rest his head on her soft little body while he wraps his arms around her.
Some of the reasons why it took me 2 months to complete this picture was the fact that these two has the craziest and most confusing proportions ever, and it's still pretty difficult for me to put them together so close (while making them look somewhat comfortable) because of Buzz's bulky upper body...
Speaking of their proportions and stuff, I love the contrast between their designs: every part that is big and/or bulky on Buzz is small and/or thin on Jessie.
I think it's utterly adorable.