@Tenafly Viper
 
Interaction.
 
Wait, this is the fandom that interprets anyone of the same gender standing next to each other as totally damn homosexual and craving for their private parts.
 
Yeah. What’s next, pretending you’re actually a pony inside a human body?

@Background Pony #6F2B  
no kidding I was expecting a Raarity pillow too hehe

@SpikeSpiegel  
I meant in the sense that he has literally been with her since he was born. Have you never heard of the Westermarck effect?
 
Also, I’ll thank you to not instantly generalize others based on single comments. You only make a gigantic ass out of yourself.

Damn, Spike, were they sold out of the Rarity ones?

Twilight is less than liberal with her hugs and cuddling. Poor kid. Every child deserves to have at least one person in their life who they can feel “safe” with and go to for physical re-assurance whenever they need it. Has she hugged him at all this season? I imagine that Spike saw one of these for sale in a less-than-retuable stall in the market and bought it just so he’d had something to hold, not knowing what the majority of stallions do with such pillows. Twilight discovers it and, caught in that odd place of not knowing what he wanted it for tries to figure out why he has it. Cue discussion about how they see each other.

@Background Pony #900A  
I think it’s true, at this point Celestia and spike’s past may have been changed.
 
The lack of interaction between the two, matched up with the fact that even when they are on screen together, Celestia notices and talks to twilight yet doesn’t even talk to him once, shows that they aren’t that close.
 
I think since twilight was too young, and Celestia being a busy princess, only the maids and servants took care of him. In celestia and twi’s spare time they visted, and taught him how to send letters.

@Neizd  
The fact that there are still people who see them as mother and son is both hilarious and sickening.

“Mothersistalover drama” needs to be tag.

@Neizd  
However, after Faust left, a lot of her ideas regarding the characters and the show were dismissed, and considering the things that have been happening after the second season (e.g. Dragon Quest, The Crystal Empire Part 2, Princess Twilight Sparkle part 1, partially Equestria Girls) I can say that the writers have been taking more of a motherly approach to their relationship along with a weakening of the Celestia/Spike one.  
Now Im going to leave it at that before Parkinson strikes my fingers.

@Neizd  
Nice to see you here. And I agree with you. This is exactly what Lauren Faust said: Here’s how I had it worked out–– Spike was actually raised by Celestia while Twilight was her student. Dragons are all mysterious to ponies. They don’t really know much about them and had never seen a baby one before so Celestia took on the challenge herself. While raising him, she was able to train him to do that whole magic letter sending thing, and Celestia put the two together knowing that would come in handy one day. Plus, Twilight hatched him, so it was only fair to let her stay in his life.

@Neizd  
Still makes her a big sister figure to him at the least.

Cute beyond words but a little strange considering their relationship is that of two best friends ^^
 
And for those who say she is his mother: No. Lauren Faust said that she intended for Celestia to be his motherly figure because when Twilight helped to hatch him, she was just out of magical kindergarden… (probably around 6 years, maybe less given her high intelligence).

@Hogtree Octovish  
*why would you need a body pillow?

On a less serious note, why would you a body pillow when you can snuggle with the real thing pretty much whenever you want?

@SpikeSpiegel  
Given that we’re dealing with a sapient being with his own hopes and dreams (well, for a cartoon character) rather than just being hatched for food purposes, I’d say it’s apples and oranges.
 
No matter how Spike perceives Twi, she’s still a major part of his birth (even if it’s just as some form of unintentional midwife-like position).  
So it’s very likely that he views her more as family than anything else.  
Also, your example of birds falls flat due to the phenomenon of imprinting in some avian species (so, technically yes, in a sense, you could be viewed as their mother).
 
Honestly, I’d see that as less creepy than if he viewed her as a potential sexual conquest but, as you say, some Bronies do have a weird way perceiving relationships. :P

…She hatched him. I hatched chicks on my Dad’s friends ranch with an incubator. Doesn’t make me their damn mother. Bronies have a weird way perceiving relationships.

@Background Pony #556B  

@Tenafly Viper  
but shes not his mom! Spike himself says so!

That’s a lil’ weird, Spike.
 
Especially considering that, since you were given to her literally as soon as you were hatched, she’s kind of like your mom…