The plugin gives every player a default stomach build. Preds who want their own custom build can make one and set it as the place prey appear when eaten.
/vosetgut.You can change the position and orientation at any time by standing where prey should be, facing the right way, and running /vosetgut again.
The Art world is recommended for stomach builds, since it gives you creative mode and customizable plots. Get there with /warp Art. See Creative World for how plots work.
Each Vore Type has its own stomach spawn point, so you can keep a different build ready for each one. /vosetgut sets the gut for your currently selected vore type.