Will a person become dependent on using a vibrator? Will they still be able to orgasm from, let's say, oral sex or vaginal sex? If that's your concern, then rest assured that there is nothing about vibrator use per se that will deny a person the ability to have orgasms any other way. I've worked on a number of research studies related to the use of vibrators and other sex toys and many women and men experience orgasm in a variety of ways.
That said, I do think it's a good idea for people to vary their sexual experiences, whether we're talking vibrators or other ways of enjoying sexual pleasure. When you masturbate, vary your hand and body position. Use lube sometimes but not other times. Include a vibrator sometimes but maybe not every time. If it's been a while since you've been open to receiving oral sex, consider inviting your partner to go down on you. By varying your experiences, you can help keep your mind and body receptive – and responsive – to diverse types of stimulation and sexual pleasure.
Generally speaking, many women and men find that orgasms occur more quickly while using a vibrator, assuming one is using a vibrator (and intensity of vibration) that they like. Some couples using vibrators during foreplay or intercourse to ease orgasm for one or both partners. The We-Vibe is an intercourse-specific vibrator (it can be worn vaginally by a woman during intercourse). Other vibrators, such as the silver bullet, are small enough that they can be held to the clitoris, scrotum or other preferred parts during intercourse.
Dr. Debby Herbenick, author of Sex Made Easy and Great In Bed, is the Co-Director of the Center for Sexual Health Promotion in the School of Public Health-Bloomington at Indiana University (IU) where she is a Research Scientist. She is also a sexual health educator at The Kinsey Institute for Research in Sex, Gender and Reproduction where she writes (and hosts audio podcasts of) the Kinsey Confidential column and coordinates educational programming. She has a PhD in Health Behavior from IU, a Master's degree in Public Health Education (also from IU) and a bachelor's degree in psychology from the University of Maryland, College Park. In addition, she is certified as a Sexuality Educator from the American Association of Sex Educators, Counselors and Therapists.