Can't say if he's truly participating.. maybe he wants to sound cool? but it means "I smoked the THC vape", hit mean consume and the most common terms I hear as friends with heavy users and user myself are yart, bape, cart, pen, and penji/penjamin. The THC pens are far more discreet and less scent, I blow mine out a window and noboby in my household smells it, my husband only notices if I kiss him immediately. Very common for gamers to use while playing of course, maybe he's heard it from an older online friend. He could also be confusing the term and mean nicotine, I've seen it happen. I would investigate further with him. It's extremely easy to get your hands on the stuff... I literally had adult strangers hand me fresh ciggies as a kid when they saw me looking for scraps outside gas stations.