Bare Knuckle boxing is a slang term for participating in sex without using any protection, resulting in skin on skin contact. Similar to boxing without gloves.
A diplomatic gesture like a handshake or a greeting that clearly and civilly demonstrates the fierce and unrelenting determination of the part making the gesture.
"Such acts are against diplomatic ethics and norms of international relations. Nothing is more reprehensible than such bare-knuckle diplomacy." - chinadaily "Bare-knuckle diplomacy shames only itself: China Daily editorial"
“Yo, the cops just raided that Korean massage joint around the corner!”
“For real??”
“Yeah, they got busted for serving out $15 bare-knuckle hand-pulls.”