Sometimes that happens to me and it's usually when I've eaten things that tend to thicken the stool. Have you tried just gently running your hand over the bag and stoma to work the stool down when you feel it gathering there? Often if a little bit gets stuck there initially things just start building up and the problem just gets worse and worse. If you have a two-piece system try just opening it a little(like you are going to burp it) and run a q-tip around your stoma to loosen the stool that gets stuck there. I also suggest maybe drinking a glass of grape juice at least once during the day as it will flush things out and perhaps prevent the stool from building up there. I was having problems with chronic blockages as a result of some post-op complications (which have finally been corrected) and I find that drinking the recommended 8-10 cups of fluids each day and including things like tea and grape juice really helps keep things consistent. One other thing...maybe it's the product that you are using. For whatever reason maybe your stoma and the bag don't work well together. Have you tried using a convex barrier so that less of your stoma sticks out? A convex barrier might allow the stool to drop more directly into your bag instead of having it get stuck there.
PS: There is nothing too embarrassing or too bizarre to talk about here. While ostomies may not be the ideal topic for dinner table conversation, that's what we all share and are here to discuss. Don't ever hesistate, just ask.
Re odor probs: The only time I notice odor is when I change a one piece or empty a two piece appliance. If you are "constantly" smelling yourself, then maybe you don't have a good seal? Tell us more.
LOL, LOL re added garlic scent
Betcha didn't do that more than once!