Hello!
The meat uses VRCFury for attachment, this is a package for Unity which will make attaching the meat as easy as just dragging and dropping it onto your avatar in the unity scene before upload. There are more detailed instructions included with the horse meat package as well.
It doesn't come with a cum animation because I like to keep the meat relatively simple. And because there's other solutions out there! A lot of people I know use https://pleasurearcade.gumroad.com/l/thiccwater Thicc Water for cum effects.