Best feeling of my life - teenage debutant Douglas
Written by I Dig SportsDespite his lack of club rugby, Douglas has been earmarked as a hot prospect for some time now.
He was Scotland's standout player in the Under-20 Six Nations, making the most tackles and breakdown steals in the tournament, and it is a mark of how highly Townsend and Scotland rate him that he was thrust into the international arena so young.
And yet, when he was introduced, to the acclaim and excitement of the Murrayfield crowd, he was not overawed by the scale of it all.
"I thought he was really mature on two or three occasions," Scotland's record points-scorer Chris Paterson said.
"You've got that burst of energy, it's your first cap, you're known for turnovers; his decision-making, knowing when to go in was really mature. He listened to the referee."
Douglas played down his lack of experience and says White - who was at Murrayfield as a spectator - was keen to remind him that he isn't the youngest player to pull on the dark blue of Scotland.
"I don't think age is really what matters," Edinburgh-born Douglas added. "If you're good enough, you're old enough.
"Meeting Donald was amazing. He was lovely, wee bit cheeky but really nice. Class to see him. He did say that he was definitely younger than me!"
Douglas - who looked up to Hamish Watson and David Pocock growing up - credited the staff and players in the national set-up with making his transition to senior level a smooth one.
With Scotland A facing Chile on Saturday before the Wallabies visit Murrayfield on Sunday, Douglas could well be back in a Scotland strip before long.
"[International rugby] is a big step up," he said. "A lot quicker, a lot more physical.
"Playing and training with my heroes growing up, it's all been a bit crazy. They've all been so welcoming.
"It's not felt like I'm the youngest or I'm not meant to be here. It's just felt so welcoming and special."