I wonder if there's a story behind this? I did most of my scholastic work sitting on my bed (unless I needed to write or use a computer), so maybe his pillow has sort of made the whole higher-education journey with him. That'd be kind of cool.
Either way, he's got guts carrying it across the stage with him.
That's funny, I honestly admire his guts to do something like that. I'm known around school for liking Miku so I was considering making my yearbook quote something related to her but then I thought "hmm, no, I'm going to regret that someday." So I have mad respect for him pulling this off.
It's not a full on body pillow, but still pretty big (kinda NSFW picture). I bought it from a con, but I'm sure you can find it online too. Her actual (genuine) body pillows are pretty hard to find, though.
I will definitely do this but not on the graduation day. There is a tradition at my school that the students of the graduating class organize a "theme week". Last year, there was a day when they all dressed up as geeks and weebs - and I will just walk along with my Miku daki when the time comes.