As we discussed above (2:4), ona is referred to as derekh eretz, which makes it clear that this mitzva must be fulfilled joyfully and pleasurably, as is the way of the world. The mitzva is not meant to repress our natural desire, but rather to express its holiness and channel it properly, so that it will last through the years. There is still room to ask: should a husband and wife increase their passion and try to maximize their own joy and pleasure, or is it enough that they are aroused to give each other pleasure?
It would seem that we can apply an important halakhic distinction here – between mitzva and makhshirei mitzva (prerequisites or things that facilitate a mitzva). In this case, the mitzva incumbent upon the man is to bring his wife pleasure. His own enjoyment facilitates the mitzva as it increases his passion and desire to bring pleasure to his wife. According to halakha, makhshirei mitzva have the same status as the mitzva itself, as long as they are auxiliary to the fulfillment of the mitzva. In other words, when a husband gives his wife pleasure, then his enjoyment is also part of the mitzva. The more pleasure he brings her, the greater his mitzva. As a consequence, his personal pleasure is likewise considered a greater mitzva. In contrast, if he does not manage to give her pleasure, his own great pleasure is no mitzva. There is only the basic benefit that it saves him from sexual transgression (as explained above in sections 3 and 5).
Likewise, when a wife gives her husband pleasure, she fulfills a mitzva, and her own pleasure facilitates the mitzva. The more pleasure she brings to her husband, the greater the value of her own pleasure.
Let’s take this a step further. When a wife wants to enjoy their sexual union, and to that end she opens up to her husband and allows him to bring her great pleasure, she is enabling him to fulfill his mitzva. Thus, her pleasure facilitates the mitzva in two ways: she helps her husband fulfill his mitzva, and this, in turn, intensifies her desire to bring him pleasure. Similarly, the pleasure that a husband receives from his wife facilitates the mitzva in two ways: for through his pleasure, his desire to give his wife pleasure grows, and this allows her to fulfill her mitzva to give him pleasure.