I have this pulsating, vibrating feeling in my vagina as if i'm sitting on a vibrating cell phone. what is this feeling i'm experiencing?

Penis envy?: Just kidding! seriously, it's hard to imagine a physiological cause but any peripheral neuropathy could result in a low-grade sensory experience such as "vibrating". Have you been horse-back riding? Training for a 100 mi bicycle ride? ...Boyfriend that gets carried away with "rough sex"? It might be argued as a "body memory" but that would presuppose you've actually used a vibrator of that type...