Once you enter the sphere of the Grateful Dead, there’s a decent chance some psychedelic journeys could be in your future—a fact that Bon Iver mastermind Justin Vernon apparently learned last summer.

A new Pitchfork feature, which follows Vernon around his hometown of Eau Claire, WI, closes out with the singer-songwriter trading stories with his bandmates at a hotel bar as they prepare to kick off rehearsals for an upcoming stadium tour in support of new album i,i. Vernon and his guitarist, Andrew Fitzpatrick, look back on “their time taking acid backstage at a Dead & Company show,” which seems to also be the time Vernon sat in with Dead & Co., when the band played Alpine Valley in Vernon’s home state in June 2018.

Looks like Vernon is yet another musician who had the pleasure of tripping while playing on stage with members of the Dead. Bassist Oteil Burbridge lauded his own experience in that category three years ago, and it appears that Vernon quite enjoyed himself as well.

This likely wasn’t the first time he’d dropped LSD during a show, though—the beginning section of the Pitchfork piece notes Vernon’s affinity for mind-altering substances: “LSD and DMT are more prominent in his life now, drugs whose therapeutic and creative properties Vernon champions. He has started to ask the crowd at Bon Iver shows if anyone’s on acid. One time, when no one raised their hand right away, he raised his own.”

And, just in case anyone was wondering, Vernon also shared his thoughts on Dead & Co.’s lead guitarist: “I am fully in on John Mayer. Hats off to that motherfucker.”

Below, watch video of Vernon’s sit in with Dead & Co. on “Bird Song” and “Black Muddy River.”