tail lights not working

I have a 2003 infiniti g35. My license plate lights were blinking so I took them out with the car running. (it's night time) after touching the lights, the tail lights went out, as well as the radio and clock lights. (the brake lights still come on when the brake is pressed). I checked all fuses in the fusebox next to the battery, and all the fuses in the interior next to the pedals and all are fine. what could be the problem?

My friends 350z just had the same exact problem tonight too after messing with his car.

thanks for the help