Yes, I can come without using a vibrator. Actually, I have trouble bringing myself to orgasm *with* a vibrator. Or with my hand, for that matter. Masturbation feels good, but I've only managed to get myself off a handful of times so far.
It's hard for me to achieve sometimes, but it does happen. Sometimes it takes a while. My Husband on the other hand can get me off in just a few mins. I have kind of spoiled myself between my toys and my Husbands magic which is probably why it is harder for me to achieve myself.