My question

Ok so I'm new to sec and all this stuff and I have a girlfriend but she lives far away (I'm a girl btw) But I have never done anything sexual like masturbation or anything and I feel so left out.... But I wanted to ask if its normal to get bad urges to have sex or something like that. I feel like a slut because I have a girlfriend but I crave sex from a boy and I'm afraid to tell her....Please give me advice for masturbation with girls because all I know about is with guys... And I want to be ready when my girlfriend wants to do things with me... Please help ;-; thank you!