New masturbating technique

Ok girls, so I got in on the masturbation game pretty late in life compared to most people I know (17), and I almost always use my shower head. It's amazing, but when I'm at school and don't have my removable shower head, it's much harder. I'm still a virgin, and so I don't even know what it's like when you actually have sex, but I can never cum when I use my hands, it just does nothing for me. I've also used an electric toothbrush and it works ok, but it takes way longer than my shower, and it's not nearly as intense. Any suggestions on other things I can try or how to change my technique? I'm also really nervous that when I do have sex, I either won't be able to come, or it won't be any good compared to when I masturbate. Help!!