You can inject subq abdominal fat with an insulin needle. You can inject multiple times a week in smaller divided dosages for more stable levels if you wish.
It's easier than injecting deep into the muscle with a big needle. That should be reserved for bodybuilding dosages. If you get an abcess, getting one deep in the muscle is a much bigger problem than in subq fat. No need to worry about hitting nerves or a major vein/artery.
It might hurt like fuck the first few times during injection but the body gets used to it somehow and it stops hurting.
This advice doesn't apply if you are really lean.