I want a bigger butt should i rub fish oil on it or swallow them with vitamin e?

Wow--NOT the answer!: A healthy/meaningful gain in lean body mass is an okay goal--but you can't pick where it goes with supplements! don't take stuff with ridiculous claims or that risk overdose or your health. Exercise vigorously, eat balanced meals, stay hydrated. Explore medical reasons why you have difficulty gaining--thyroid/ adrenal problem, diabetes, malabsorption, pancreas insufficiency, crohn's, infection...

Fish oil won't do it: Squats, lunges (including backward, side &d curtsy lunges), step ups, hip thrusts, Bridge (including marching & single leg bridge), quad hip extension, donkey kicks, single leg deadlift, fire hydrant, split squats, frog pumps & fire hydrants can all be used to work on butt muscles.