Juiceboosting
The act of plugging in a phone, tablet or other electronic device charger into a (typically public), unsecured, unauthorized electrical outlet. Frequently performed in order to make an emergency call or text, but occasionally just to charge up the battery enough to make it to either the next juiceboosting location, or to an authorized charging area.
"Check out the guy in the middle of the mall juiceboosting his phone so he can keep texting with his girl."