So basically you get to pick anything that you can possibly imagine. You can be from a Jabba the Hut style species, you can be a sexy Nord, you can be a tall green Amazon woman who has as many slave males as she likes (or just your favourite), you can be from a race where all the dudes have 7-9” dicks and there is 200 hot women for every man on the planet, you can be humanoid species that has any sort of sex with no rules, or you can be a species which enforces monogamy, or you can be a big, egg laying earth worm. Your species may be promiscuous, heavily regulated, marriage compulsory, marriage illegal. Whatever you like, the only limit is your imagination.