That new phenomenon is called “splitting the G,” in which drinkers try to swallow enough beer on their first drink that the line between liquid and foam ends up halfway through the “G” of the Guinness brand on the glass.
(There are variations, like getting the line to land between the text and the brewery’s harp logo just above it, as well as online arguments over the proper procedure, as might be expected from any internet trend.)
It sometimes shows up in the form of a bar bet, in which a bartender might offer to pay for the pint if a drinker can split the G perfectly on the first try, or as a competition between friends to see who pays for the round, or just as a bit of fun.
Can You ‘Split the G’? How Gulping Guinness Became an Online Phenomenon Evan Rail, Vinepair