General outline...
- Introduce readers to heroines
- Kwazeth - Twi'lek-esc design, photojournalist for an intergalactic travel magazine
- Yspa PhD - Half-orc-like design, exo-biologist and poet
- Shore day mishap
- One of them tumbles into what locals say is a geyser-powered tar-pit
- Sexy shower/bath scene as the goo-covered partner washes off and then finds themselves mentally linked with a new intelligence
- Both converse with the entity
- It, of course, has no idea what sex is since it reproduces by division
- Both merge with half of the entity, kicking off transformations
- Sensual scene as both adapt to entity-augmented lovemaking
- Denouement - Entity finds their own humanoid shape