The little yellow dot shows the approximate location of my implant, and the red circle shows where the sensations are strongest.
To be honest, I have no idea what is causing a pulsing magnetic field during data transmission. The antenna is in close proximity, but the sensations directly over it are much less pronounced than other areas. Also, transmitting antennas produce electromagnetic waves (which don't wiggle magnets) - not magnetic fields. Perhaps the EM is inducing a magnetic field in the nearby speaker (directly above the red region in the picture.) Regardless, it's kind of cool to feel the 'packets' or 'data bursts' or whatever and seeing how the little send/receive display syncs up with what's actually going on.