I've used various caulks but have never found the magical one that neither dries out nor becomes sticky and tacky enough to attract dirt and dust. I know this stuff exists because all the caulked joints at a friend's house have this stuff, and it's amazing. It never dries out, but isn't tacky or sticky, so it isn't a dirt magnet. It's glassy smooth, yet pliable.
Anyone have an idea what this stuff is?