Not sure why is she an functional hermaphrodite or why she isn't constantly pregnant since both sexes shares the same hole.
About constant pregnancy :
She may simply have the same system as some plants that don't do self-fertilization
(fertilization of an ovum by a male gamete from the same individual), ie the pollen/spermatozoid can penetrate the ovum only if it doesn't express the plant's own genetic markers on their surface (if it does express those markers, it is captured by receptors that recognize the plant's own genetic markers and then degraded by enzyms).
And/or there may be genetic incompatibility between male and female gametes of the same individual, causing the egg produced via self-fertilization to die at a very early stage (Renvra wouldn't even notice).
And/Or the eggs and sperm may not share the same hole /chamber/canal at the time the eggs are ready to be fertilized.
Or a combination of all 3.
Believe me, compared to some things that happened on Earth, a functional, fertile, non-self-fertilizing alien hermaphrodite is
tame.