backchannel 

Getting someone's personal contact information so you don't have to communicate with them through a public means.

We were having a conversation on a public web site, but I wanted to backchannel her so we could get more personal.

backchannel by Biggety Big September 17, 2006

backchannel 

The preferred GOP term for anal sex.

Jared Kushner wanted a backchannel with the Russians.

backchannel by jd314 June 1, 2017

back channel 

Using a common friend as a secondary way to communicate to your girlfriend/boyfriend the things that are uncomfortable for you discuss directly with your girlfriend/boyfriend.

"Hey Steph! You're my back channel! What does Lisa like as far as engagement rings go?"

back channel by Flacker January 16, 2007