Your Doctor would smack me for this and it is NOT approved medical advice but if you are willing to let your sugars run high for a few days, simply cutting back on your insulin will allow you to drop a few pounds really fast

Can be dangerous

The "much safer" way is to go on a reduced carb diet (even half what you currently eat) and likewise cut back your insulin in concert with - body fat is extra carbs + extra insulin, so if you starve your system of "both" for a bit, you will start burning that body fat that is being stubborn

Intermittent Fasting (with your Doc keeping an eye) and near total reduction of your Bolus shots while doing it can also be effective but just for short periods of time and definitely with professional help/monitoring