They're talking about the option that you have to pry into gale's mind when you first meet him.
You are using the tadpole, int he sense that you all share a connection, because of the tadpoles, and you're using that connection to attempt to read his mind. It's not an Ilithid domination ability, like they introduce later - you never use those on companions. Instead, with companions, you just probe the innate connection that you all share by way of the tadpoles. You get several other opportunities to intrude on your companions like this later on as well. They aren't counted as the same thing as when you use your tadpole to influence someone who doesn't have one.
