Help with Gigantophis (giant snake) controls

[Misfit]

So with this mod which I absolutely love despite not using it much, I’ve encountered a problem. When I try to constrict, nothing happens. It says that a target is valid however when I hold space, nothing happens. I’ve tried pressing m1 and m2 which also don’t seem to do anything. Also with the extra controls with needing me to press “leftcontrol + add” all that happens is my character whistles. Does anyone have any help with these?