Bow chicka wow wow is a nonsensical phrase, with quite a lot of hidden meaning.
It can either be an onomatopoetic expression, for mimicking the funky drum riffs found in the background music of striptease bars, as well as a euphemistic phrase for sexual activity.
The exact origin of the phrase in not confirmed, however, most sources, including Wired cites Jordan Brady as the inventor of the expression, which was part of his “Evening at the Improv” program in 1989.
The expression was first defined on Urban Dictionary in 2003.
“Bow chicka wow wow” started seeing popular use following 2005 and was further popularized by Mike Posner who used the phrase as a song title on his 2010 debut album, titled 31 Minutes to Takeoff.