'Kony 2012' Founder Jason Russell -- Sued for 'Threatening' Nude Tirade

Jason Russell -- the co-founder of the Kony 2012 campaign who had that naked meltdown in public -- is being sued by a woman who claims she was emotionally traumatized by seeing his junk.

In her lawsuit, Sharona Reid says Russell charged at her naked and threatened he wanted to "f**k her face" during his naked romp on the streets of San Diego. Reid claims Jason was on the verge of touching her "in a harmful and/or offensive manner."

After the incident Russell was placed on a psychiatric hold and said he went into treatment for 6 months. His family said he was diagnosed with "brief reactive psychosis" ... brought on by stress and dehydration.

Reid is not suing for a specific amount of money.

An attorney for Russell tells TMZ the lawsuit has "no merit whatsoever."