@MrPones  
I think it is supposed to be a deeply emotional representation of how awful rape is, what’s with all the tears and her cutie mark getting washed away alongside them. To see the cutie mark drain like that could mean that the caring, fragile and kind mare was broken and is no more due to the ongoing act of violence and yadda-yadda. The R34 sign on the gag also hints at how drawing sex with these characters is making then less pure or whatever.
 
As for me, I am here only for the porn, plus I don’t get the whole rape drama so personally I prefer to view this as non-consensual magic drain and cutie mark removal by one of the new villains who prefers to subdue mane6 instead of killing them and that dildo is actually another artifact of sorts that does its job in a lewd manner.

@greaterlimits  
I think this is one of those situations where it could be either rape or consensual submission play (my preference in this case), which people can really get into.  
On the fiction of the canvas it’s all open to interpretation.

Rape?

Yay, color!