I race sports cars and had to figure this problem out on a different scale for obvious reasons. My solution in the race car that transferred to street driving is to slide the lap belt under the bag/ostomy support wrap. This way, the lap belt is on my waist completely and the bag is not in the way of the belt. It's not the prettiest arrangement once the racing seat belts are all connected, but who cares, right, as long as they can hold me in the seat. The same goes for my street cars; once I'm in and belted, I'm comfortable and I know the lap belt isn't going to squish my bag. I wear a Nu-Hope support belt, 6 inches tall, and an Ostomy Secrets support wrap, the women's version because my body fits the hourglass shape better. That hourglass fitment has been a fantastic find as it greatly improved the fitment of shirts. Hope this helps!