One morning after vigils, while I was still in the monastery, our Novice Master celebrated an intimate Mass for one of my best friends and brother in the novitiate. Br. D was preparing to leave the monastery that day and Father felt a private, more casual Mass would be a nice send off - right after vigils. Father was vested the same as the priest in the photo, and Mass was celebrated on a little table just like what is shown. The three of us sat around it throughout, in a little speak room of the Guesthouse. That took place in the summer of 1975.
So once again, I contend this kumbaya style of Mass could not have originated with teen Masses. Instead, I stand by my assertion that the relaxed-fit Mass was a novelty that gained popularity in and through the Charismatic Renewal. BTW - Fr. Master also had the gift of tongues. I know! (Yes he did D - he prayed over me in tongues - LOL! And yes Michael, it was at NM.)
Photo: Florida priest presiding over teen Mass in 1987. Yes the priest is a guy.