You should just need to install the mod you pulled the tail from it will have the xml file needed for the tail. The mod will not need to be active, just installed so the mesh can use the xml file.  Also what mod did you pull the tail from, I only ask this because the mod by Deserter X on Nexus does not have a smp tail.   https://babofactory.blogspot.com/2020/06/bhunp-3bbb-dx-succubus-armor-se.html is the smp ver.