>>3008197THIS.
Vaginal douching flushes out all of the bacteria in the vagina - including the 'good' bacteria that keep the vagina's pH healthy. It actually causes an increase in odour and occurrence of yeast infection because of the disrupted balance of 'good' and 'bad' bacteria. If you feel you need to douche because of odour or discharge, you almost definitely have some kind of problem, whether it be an infection, STD, or pH thing...
It's one thing to want to be clean. I like to wash myself off before anyone goes down on me, because... it just doesn't feel right otherwise. I don't like to feel unclean. However, it's another thing entirely to completely ruin the delicate environment of your vagina.