Interesting info about that and it makes sense to me also.
I feel that there is Lust and there is Love. Unselfish love is the highest form of love and when two people are spiritually mature, their quality of sex will be a higher vibration than two people who live on a more selfish level and see what satisfaction they can get from each other.
So there are different levels of sex. The level all humans were ultimately designed for, and which is the most satisfying on all levels is the Unselfish love type, where the two people enjoy each other playfully, yet also express their giving to each other, and their surrender to each other. Also when a women allows the man to have fun being dominant over her for a change, as well as vice versa sometimes.
Unselfish sex of the highest form is when the couple are in ecstacy when they can give total enjoyment and love to each other like a child would love giving someone they love the most attractive precious gift to someown they love, just to make them happy.