Attempts to mix business with pleasure are always rather strained. The pressure is on to be a social sensation and you must be on your guard to ensure professional success…
Make sure you participate in after-work drinks and socials. Keep a track of who's bought what, and know when it's you round.
It's tactical to socialise. Although it can be more fun to mix with the underlings, your boss should neither be besieged nor ignored.
Be confident and friendly. Be armed with a few social icebreakers (extra-curricular activities, families, relationships).
Just because you're off campus doesn't mean that you're out with friends: colleagues and bosses are still just that even in the pub at closing time.
Familiarity comes with time, so be aware of unspoken barriers. Avoid strong opinion or stark honesty; occasional frisson is interesting, but controversial views may offend.
Ask questions but don't interview - there is a fine line between interest and intrusion.
Never talk about money, illness or death. Bluffers and serial liars always get their comeuppance; name-droppers and braggers bore everyone.
Alcohol might be a key ingredient but apply the usual rules of caution: eat well, spike drinks with water, know your limits.