As self-respecting campers, you and your buds wouldn't dare sit on the bare dirt would you? You would show you camping-craftsmanship to the utmost to provide a comfortable seating for you and your buds, whilst using only that what you find in the wild and your trusted Knife. You will show that you are a real camper and make Log Seats!
You can sit on a Log Seat by right-clicking it.
Remember, you rotate any rotatable block in Minecraft by right-clicking it with a Knife, this also applies to Log Seats.
To craft a Log Seat, a log and a Knife are required.