This sort of ties in with my reply on your other thread...
If you do a search there are other threads on lubes, but yes, there are organic/natural ones available, like Yes. If you find a lot of clients do RO you can buy flavoured ones, but they're more likely to be synthetic/irritating. KY Jelly is medical grade and neutral so a good option, but may not be great if PIV penetration is prolonged. Silicone lubes are smoother/slicker and last longer.
It may also help to use a vaginal moisturiser like Vagisan or Replens overnight.