According to the ancestral knowledge passed to all children of the world, lava is unable to melt any sort of man-made furniture. Therefore, I'd remain in my lava-proof bed and continue browsing NUF... And if I got hungry or needed to go to the bathroom, I'd use a chair with wheels to get there.
Pour water on the floor to transform the lava into obsidian. A thousandth post well spent, I say. Denying any accusations of being a pervert (though whether it is true or not is a separate question). Aside from that, congratulations on your thousandth post.
I would row, row my boat couch away on lava while I can before it melts and before I indigest all the radioactive toxcity in the air plumes since lava comes from deep down earth's crust where uranium and godzilla sleeps.