The Soft Ones are sapient, gaseous lifeforms that inhabit a small rocky planet located in a parallel universe from our own. They have three different genders: Rationals (or lefts), Emotionals (mids) and Parentals (rights).
The Soft Ones' language consists of pulses.
Barlowe's Guide to Extraterrestrials - Wayne Barlowe
Soft Ones are able to feel the position and emotional state of other members of their triad, though, again, this is only to a certain extent. They reproduce by melting, which means fusing into one another, and this can only be done with the participation of one of each of the three genders. The Emotional provides the energy, the Rational the seed, and the Parental the incubator. The melting can last for many days and during this time participants remain unconscious.
It is the Rational who decides when the time has come, and when this happens the entire triad, Rational, Emotional and Parental, will melt together for one last time and pass on.
As it turns out, Soft Ones are actually the immature stage of Hard Ones. When they pass on, they do not die as they often believe, but rather become a Hard One. The three members of the triad, Rational, Emotional and Parental, melt together permanently into one sole individual, which explains both why Hard Ones have a dense, solid body and why they are in smaller number that Soft Ones. The reason why Soft Ones are never told this is because the Hard Ones believe that only when the Rational is able to find the truth by himself will he and his triad be mature enough to pass on to the Hard One stage.