Which type of rubber pants

I have been recommended to wear rubber knickers (underpants) for sanitary reasons, but when looking at what is available there are basically 2 different types and my doctor didn't advise any particular style or pattern.
There are those rubbers which are slightly baggy with elasticated leg-openings and waist and those which are also waterproof by being skin-tight and I'd like advice which would be the better of the 2 and is there any danger of wearing latex rubber undies becoming a fetish?? Any advice would be appreciated. Thank you.