Done naked, post rugby game, opponents welcome. One arm under your crotch gripping your mates
hand similarly placed, your other arm gripping the dudes hand in front of you. Singing something like "We all going on a Lion Hunt".
All the rest is bogus. Sphincters, dick grabbing etc., are knock offs by twits if they exist at all.
Best
done at the bar or the Common Area if it's late enough.