We really need more dominant female stuff.

@hentaispyder  
Though you present a good logical analyzation of the pairing, this was a femdom request. However many times I commission these two, Trixie will always be dominant.

While it is lovely, I just don’t see it happening. Not without a very good back story at least.
 
If you were to change the eyes around; though, it might be more possible. Trixie seems more like the “tsun-dere” type, so if Spike took the lead (ie. Trixie on her back while Spike stands on her, maybe pinning back her shoulders, while starring in to her eyes) I feel like that would work.
 
You see, I can imagine her as the type that wants to be in control, but she’s terrified of being alone (again) which happens a lot because she pushes too hard to be in control and all the other stallions leave (or for a sadder story, just use her.)