Interesting question. I wonder how long it will last before it devolves into a somewhat less serious topic. 
I will try to answer seriously, though. I think that shoehorning “gender politics” into a sexual act or position is somewhat inappropriate. If such politics come into play, it is not as a result of the act itself, but rather as a result of the intentions and motivations that are behind the act… things which change from individual to individual, and from encounter to encounter.
Take these examples, and consider how the gender politics change from on to the other.
Example (A): Susan is in a relatively happy marriage with a man who, on occasion, expects to receive fellatio. She doesn’t particularly like to do it, and feels that it is somewhat demeaning, but does it to please him. The expectation is that she’s the wife, so she gives her husband this pleasure occasionally.
Example (B): Georgia is in a relatively happy marriage, in which her and her husband both enjoy some light bondage in their sex. One of their mutual favorite positions is him being tied up/handcuffed on a bed while she performs fellatio on him. She feels powerful and sexy while doing it, and he loves the attention.
These are two examples… basically the same act (fellatio), but I think you’d agree that the “gender politics” of each are quite different. To my mind (A) puts the man in the power position, with the woman submissive. (B) sort of does the opposite (though this is debatable too), putting the woman in the dominant role. There are infinite variations of this, many of which put neither man nor woman into a “power” position, but in which both are equal pariticipants. It is not the act that defines the gender politics, but the individuals involved and the nature of their interaction.
One further point is that these things change over time. To get slightly personal (possible TMI here), for a long time my wife felt that sex with her on her knees and me behind her was demeaning. I could see what she meant, and I respected her view on it, so for a long time I avoided that position in our repertoire. In a relatively recent development, she now very much enjoys that position, and will tell me so. If I were to interpret the “gender politics” at play here, I would say that early in our relationship, she felt degraded in that position. Now, however, she feels empowered by her willingness and ability to know what gives her pleasure, and to get it. Same act, but a change in perspective (and experience) gives it a different spin.
I don’t see that gender politics are inherent in any particular act or position, but only in the motivations of the participants.
There. Hopefully that was kept relatively highbrow.