Should i be a bottom

Iam 18 i have a big jiggle ass but iam not fat just my ass is fat so i was straight but last year i start feel more satusfied when someone slaps my ass or when i wash my ass with soap and i tried finger my self i get relifed so should i be a bottom ? And what is the best thing besides dildo to use when one of my friends slaps my ass for fun i feel satisfied
And every time i saw a gangbang videos i want to be the one who get fucked