Can be depicted as either a lifestyle of a person who smokes marijuana frequently or as a depiction of "the good life", aka money, friends and good times.
Jimmy has been smoking weed a lot this summer, he's definitely living the highlife.
Sarah rented this crazy penthouse suite and had parties all weekend. Definitely living the highlife.
The 'real' life with friends, girlfriends/boyfriends, music, parties and coffee shops.
Niklas couldn't play stratego with his geeky friends cause he was busy with his highlife.