I'm a Bitcoiner & not particularly concerned with what is socially acceptable.
This topic was covered at an Australian Bitcoin Bush Bash about 20 months ago. It became known as the Bush Bash of man huggery.
The agreed protocol was that your left arm is raised & your right arm is lowered in the embrace. This orients your bodies so that your hearts are aligned & meet in the hug.
It lasts as long as it lasts & pats are optional.
It was weird at first but it's part of our culture now. Once that left arm goes up, you know what's coming.