The smooth metal dome attaches to your finger with an adhesive pad. Because it is rounded, it fits nicely on the tip of your finger.
The point of the needle slides across the dome smoothly. You can't exactly feel the point of the needle but I can easily tell where it is.
I've sewn more than a week with just one adhesive pad. There are 8 pads in the package and you can order replacement adhesive pads as you need them.