Yes it its safe, i believe that many people do it. you could protect yourself by the lesser banishing ritual of the pentagram before you project.
Experiences can vary. At first you may need to get used to it, and seeing you're body or getting too exited or scared when you project can get you pulled back into your body. You may travel to weird or distant places or you might stay in your house. It kind of depends on where you choose to go.
If you think you are projecting, you can test it. Say you think you see your friend reading while you are projecting. Think of him doing something else, like making cookies. If he changes what he is doing according to what you are thinking, then you are not projecting. Ifhe continues what he was doing before, than you probably are.
You can travel to other places, or get back to your body by basically just thinking of it, or willing yourself there. When you go back in you're body, you may feel a falling or pulling sensation. This is fine.
There are astral beings that you may run into. Be respectful. They most likely will pussy little attention to you, unless you start interacting with them. You could also talk to spirit guides through projection.
It is an interesting experience, requiring practice and persistence. While projecting you may feel lighter or "floaty". Leg motion is not necessary while projecting; you can move by just willing yourself to.
Information taken from:
Techniques of High Magick by Francis King and Stephen Skinner