Ever seen a dolphin with a wiener?`
Didn't think so.
Apparently it's folded in some skin fold for performance reasons, not sexual performance but speed and agility underwater.
So maybe the Vasudans have it some similar way, because they must somehow combine DNA to reproduce or maybe they have no female Vasudans, I can't ever remember meeting one in any of the two games. Maybe they're like earthworms, can swap gender as they like and reproduce like fish, no need for humping. Hmm.