Someone who is doing things expected of a fat person. Not usually an insult, as the fat biffer is almost never a fat person. Usually heard in the south of England. Is said quietly, and never with a tone of shock or surprise. This makes it sound like the fat biffer does this sort of thing all the time, though in truth he rarely does.
Dave in pub: Pint of Carling and two pies please.
Other dave: You fat biffer.
When you're jacking off to porn and when the video stops to buffer you become too impatient for the video to resume so you just cum during the buffer screen.
"Dude I was watching this Dillion Harper vid last night on my phone but I only had 4G."
A buffer guest is a close friend that you invite to a party ten or 15 minutes before the rest of the guests are scheduled to arrive. This guest or group of guests is meant to 1) make it seem like the party has already begun and good times are to be had and 2) make it less awkward in case someone you don't know particularly well arrives before everyone else.
I invited Jona over as a buffer guest in case Tim or Josh came over early, because I don't really have a lot in common with them