Have you changed her diet recently – anything new? Added anything like Basil? How long has she been "smelly"?
I agree with Sarita, bathing shouldn’t be done as it can really stress out a bunny to the point of shock. And even with the rare rabbit that isn’t much bothered, their fur takes forever to dry and this can cause problems with body temperature.
So CowieCow, looks like you are going to have to muscle up, call in for some backup from a friend or family member and pick Cowie up and check out her underside and possibly spot clean her backside with luke warm water if need be or clean out her scent glands.
Here’s what I suggest . Use a towel to put her into a bunny burrito. Have you ever done this before. If not check out the monthly maintenance section and scroll down. My Jack DESPISES being held and being prodded and probed. So this is the only way I have found that makes it easier.
You still have to be careful that when you expose the hind area, the Cowie doesn’t kick out into the air and injure herself. So you’ll want to have her legs pressing against you or a pillow.
Also, when you are first doing this, and if you are still feeling a bit unsure, then it’s best to be low to the ground, just in case she does make a break for it, she’s not far from the ground.
If you find out she’s had a messy pooter, then you’ll need to spot clean. I usually run warm water over that area and work it all out. No fun.
Let us know how it goes!