It’s important to use water-based lubricant with condoms, as without it, they are more prone to breaking.
Using lubricant when you have sex can also facilitate your pleasure. If you are having sex with a man, using water-based lubricant helps reduce friction and make the condom work optimally. If you are using a dental dam or other barrier for oral sex, the lubricant goes on the genital side, and the mouth on the non-lubricated side.
NEVER use oil-based lubricants like Vaseline, papaw cream, hand cream or other substances as these can weaken the latex. In addition, they are not good for the vaginal mucosa, as they can clog its self-cleansing mechanisms.
NEVER use two condoms at once – this can cause friction and make condom failure (splitting, tearing or falling off) more likely.
Links:
[1] http://www.napwa.org.au/resource/treat-yourself-right/sex
[2] http://www.napwa.org.au/resource/treat-yourself-right/sex/oral-sex