Why is it that when i masturbate i want more?

ive been masturbating since i was about 11 & i have regrets here and there but i mean cmon i love the pleasure. anyways , i'm not very comfortable with sticking something in my vagina for reasons like being a virgin & i just started my period a month ago & ive never even thought about using a tampon yet. what i typically do is get a bottle of baby oil and pour a quarter size amount right about my vagina so it flows down my vagina. i then start to rub my clitoris and oil up my fingers and have quick but pleasing orgasms !