@dlowan,
Some throwing herself at you!
I wonder if cats distinguish between public and private settings. When I visited Blatham and Lola, one of their cats wouldn't even look at me when we were in the living room and he two were around. But whenever I went to my guest room to have a nap or read a book, she would open the door, jump on my bed, and cuddle up. Perhaps something similar is going on with Sebastian.