Grout Pen Waterproof Tile Marker Wall Seam Pen, for Tiles Floor Bathroom Decontamination Seam Repair

The rod is too thick, it doesn't get on the grout. And where it does, the rod simply smears the grout on itself. But it doesn't paint over it. Where should I put this crap now?

Everything arrived on time, whole, sealed in cellophane. No damage. Thanks to the sellers and to Joomall, a happy new year. Peace to all.