This specifically has to do with synastry, where one partners Venus conjoins the other partner’s south node. But the principle also applies to an individuals horoscope where there is a venus / ketu conjunction.
South node (“Ketu”) makes inner transformations/revolutions by pulling the external world inward, subordinating it to the internal “realities.” The North node (“Rahu) makes external transformations/revolutions by pushing the internal world outward and making the external world conform more closely with the internal “realities.”
Thus the south node is introversion and the north node is extroversion.
Every couple is unique, so every couple should have their unique compatibility assessment. But as a general guideline, the South Node would pull the senses and sensuality (Venus) *inward* into a more psychogical, spiritual, or fantasy realm. So the sensual experience of the couple would be felt as being mainly psychological / spiritual in nature and can have a lot to do with fantasy and fantasizing.
– Vic DiCara