The setting to allow Futanari in Sexbound is disabled by default. To be able to change your Sexbound settings, you must have the starbound-sexbound.src.zip version. Link is below. After you extract the zip files, open up the mod and look for a sexbound.config file. Open it up with Notepad (or preferably Notepad++) and scroll down to the "Load Plugin - Futanari" setting. Set "enable" : true; and done. Example can be found below.   It may be a good idea to look through the sxb_plugin.fut