We live in a culture where sex is not so much an act as a thing: a substance that can be given, bought, sold, or stolen, that has a value and a supply-and-demand curve. In this “commodity model,” sex is like a ticket; women have it and men try to get it. Women may give it away or may trade it for something valuable, but either way it’s a transaction. This puts women in the position of not only seller, but also guardian or gatekeeper … To that way of thinking, sex can only ever be transacted, and the transaction that is the most advantageous ins the one that uses the highly valuable early product to maximum advantage, to secure the best possible marriage.
The better model for sex is the one that fits the musician: a performance model, where sex is a performance, and partnered sex is a collaboration. Music is an obvious metaphor. (There are others: dance, which is also frequently a two-partner but sometimes a multipartner activity; or sport, which imports a problematic competitive aspect.)
The performance model gives us room to expand comfortably beyond the hetero paradigm. This model encounters no conceptual problem when two men or two women or more than two people have sex. Their collaboration will produce a different performance because their histories and preferences differ, as do all people’s, and the result is influenced (not constrained) by the bodies people have. The performance model even has a better explanatory power than the commodity model in looking at a queer man and woman having sex. The commodity model does not differentiate this scenario from that of a hetero couple; the performance model predicts that this union will be different.
Thomas Macaulay Millar, "Toward a Performance Model of Sex" from Yes Means Yes!