The following is an email I received in response to a query I made of an acquaintance of Fiona’s:
Lois (and Fiona),
The insertion of an NG Tube carries many potential problems, the insertion of multiple NG tubes will carry additional complications and I would strongly advise against anyone but a very experienced medical professional carrying out such a procedure, especially with the larger variant of tube.
The main risk I see is damage to the pharynx or oesophagus especially during the insertion of the second tube but as I mentioned, a medical professional will be able to mitigate that risk. Once the tube(s) are inserted the main issue, baring in mind your stated objective, is vomiting. Vomiting with an NG tube inserted could cause serious complications and the tube(s) should be removed immediately if it occurs, you should be monitored throughout your proposed scene for this reason.
To reduce the chance of vomiting I would advise building a tolerance to the urine, especially stronger urine, by drinking your own daily and gradually increasing the volume as you approach the day of the scene, it may also be beneficial to take some over the counter anti sickness tablets directly before the scene. During the scene it may be a good idea to wear a loosely fitting posture collar as it will help keep your neck straight, which is important.
Dr xxxxx xxxxxxxx