To clear up the drinking lots of water debate:
The reason it can, at times, be dangerous is to do with your blood plasma sodium levels. Put simply the problems associated from drinking too much water all develop as a result of altering your body's sodium concentration, which is used to move water around/out your body by altering concentration gradients. If you alter sodium levels too much (by diluting with water or otherwise) the body's water balance will be altered, which given we are simply bags of water can cause problems. I'm not going to explain any more in case at some point some fool reads it and decides to play around anyway, safe in the knowledge he 'knows' what he's doing.
Just out of interest, for anyone on ACE inhibitors manipulating this process is vaguely how your tablets (hopefully) reduce your blood pressure by altering blood water volume.
For the guy with oil on his tongue, go and see your doctor if you're worried. I wouldnt start doing anything, drinking lots of water or otherwise, before talking to a doctor. Hope you get it sorted out. MIght be interesting to post up what he says about swallowing oil as i suspect lots of people have accidently ingested oil from dirty hands (myself included) so it might be of interest to them.