Are oil based personal lubricants safe for the ? ?

Is using oil based lubricants like "Firefly" safe for the inside of the ? I know it's never good to put anything foreign inside your body (much less your ) but are those types of lubes good for your or bad for it? Firefly lube only contains oils from natural plants and seeds. What happens to all that oil in and on the l walls after ? Should it even be in there to begin with, or is it healthy?