Douching is NEVER recommended. Anytime you douche you run the risk of infection, whether you have an IUD or not. Your vagina is meant to have a certain amount of bacteria and you are messing with those levels when you douche.
You can but if it's that smell your worried about it wont go away until you remove it. I hated mine too I got it out after 2yrs of misery this past monday. Smells gone and I FEEL GREAT!