Slithery Heat by Roe Horvat

Looking for a no-strings-attached way to go through heat, Gideon signs up with the Titanoboa Clinic to become a surrogate for an alien species. He’ll carry alien eggs in exchange for an ecstatic heat experience, and after ten days, his body will return to normal. He doesn’t expect to befriend the odd yet charming alien, let alone fall in love.

The omegaverse romance novella contains tentacles and sci-fi themes. HEA for the main couple.