A player pilots a body through a fluid three dimensional realm. They find some mindless vegetal matter and are grazing contentedly when they scent another body nearby. They freeze and scan their surroundings listening for sounds. They become aware the other body is sending aggressive sounds their way. This could be a signal that they better run. But the player doesn't want to give up this good feeding ground. They signal aggression in return. The other goes silent. Both players are now contemplating their next move. Neither knows much about the other though so it is not obvious who ought to run. The player, having heard the other has an idea of its location and approaches boldly. This confident approach scares the other who decides to run for it. A chase ensues. Finally the other is caught or cornered and must turn and fight. In fear it sends a signal of submission and offers to make peace perhaps offering to copulate. The player thinks this weakling is hardly a worthy mate and rejects the offer and moves in for the kill. It lays its arms upon the other's body and is surprised by how large and strong it feels. Too late to re-consider it attempts to attack the other but finds itself quickly overwhelmed. Soon the player's body is rendered helpless and it is its turn to signal submission and plead for its life. Perhaps the other decides not to hold a grudge and appreciating the players boldness agrees to copulate and extend its protection to the player's body by marking it as a mate. The player agrees and now it will bear a scent that advertises their membership in the other's family. On the other hand things might have gone differently and the other could have decided to kill the player's body. Had that happened the player might have had the option to release a dying scent that would have marked the other as its killer for a time. This might have the effect of warning others of danger... or marking the other for revenge by the player's surviving kin (if any existed).
The initial encounter might have gone differently if the bodies had been able to gather more information about each other before getting too close. They could also have chosen to share more informative (or deceptive) signals.
A possible result of the copulation is one of both bodies producing offspring after a time. Offspring might be eggs or live organisms depending on various factors. The offspring will have inherited markers that indicate their parentage. They will gain a mixture of their parents attributes and they will have a membership in a particular generation. Eventually a player will die of old age, but they may have the option of being re-born as one of their own descendants gaining some genetic game play advantage by doing so.
Even when a player cannot be re-born as their own descendent, there is at least some karmic baggages that they may carry to their next life.