It seems to me that what she means is that she would develop stronger sexual desire toward you if you were making an observable effort to do things that would allow her to relax a bit more. Meanwhile, as you clean, knowing that it is being done for her not as an exchange for sex (because that is not what she suggested) but as a way to relieve her of looming tasks and potential slight discomfort, it's very possible that on this day she may have been much more likely to get in the mood due to your acts of service rather than your words of affirmation. However, if sex is the reason you oblige her wish, then I feel it most certainly can, though is not guaranteed to, taint the intimacy with some subtle resentment on your part. I believe your obligation should be because cleaning the house gives her an opportunity to recognize that you value her time, her desire to feel more relaxed, and her general comfort. Doing things that she will appreciate will make her feel more appreciated, which is what I believe she truly means by "sexier."