The throbbing cock vibe sort of does what it says. It pulses "like the real thing" at the pace of the healthy human heart. It's covered in a skin-like latex, and comes with a remote control with which one can manipulate the speed of vibration and the pace of throbbing.
I stuck mine into a tender young undergrad who claimed never to have had anything "artificial" in her pussy. Her reaction as I worked the controls was a heart-warming mixture of Fuck!, Dude! and Woah!, which translates as a ringing four-star endorsement in the UC school system.