ok, sorry i didn't clarify. you dig the hole, put beer in hole, cover hole, douse in fuel, stand back and ignite, dig them back up after flames go out (or you extinguish them) he's an old guy, but recalled his uni days doing exactly that on the beach in spare time
he's a cool lecturer, but he's better in pracs. showed us the best chem glasswear for almost any application you care to mention, including bongs, wine glasses, etc. and he figured out a way to use the distilled water distillers in the lab to distill moonshine

sounds like a drop kick when i mention all that, but he;s a great lecturer, and i learnt alot from him, including legit stuff.
p.s. i will not be held accountable for any resulting injury, damage, environmental degredation or anything for this, try it at YOUR OWN RISK.