Dont use them much

Eating less can help you lose mass/size BUT it can make you look more shredded too. (Bruce lee)
More fat on your body will hide the cuts and dips in the muscles too. (this is why bodybuilders bulk, then cut, then bulk, then cut.)
So maybe, lose mass, then add fat... but you could look more ripped on the losing weight part.
There is also the issue of health!
If you are very skinny or unwell, DONT try to lose muscle, try to put more cushion (fat) over it

Still do leg exercise such as walking, jogging squats etc because women have more leg mass than upper body but men have either equal mass or the "t-shirt body" with little leg mass.
If you struggle to put weight on, eat more and try to exert less exercise and vice versa if you have mass you dont want.
I know women that are 11st+ with arm mass but they look ultra femminine because there is both some muscle AND the girly fat on top.
Keep an eye on the stomach too, its HARD to get weight off of your stomach once it is there.
Sit ups actually ADD mass to your stomach because the ab muscles get bigger.
(If you hadtoo much face fat you wouldnt do face exercise

lol)
Generally more exercise and calorie-carb and sugar-fat control is how to attempt to remove any stomach fat.
The body really is a rubix cube and many points needed to be raised here as any change to your body can change other things too.
Ahh and increases in weight are usually kinder on the stomach fat if done >>>slowly<<< with good foods!