This is the best McLuhan conversation I found so far:

Marshall McLuhan in Conversation with Norman Mailer, 1968

[Mailer]Look Marshall, we’re both agreed that man is accelerating at an extraordinary rate into a super-technological world, if you will. And that the modes and methods by which men instruct themselves and are instructed are shifting in extraordinary –
[McLuhan]We’ve gone into orbit.
[Mailer]Well, at the same time I would say there’s something profoundly autoerotic about this process, and it’s sinister for that reason.
[McLuhan]It’s psychedelic. When you step up the environment to those speeds, you create the psychedelic thrill. The whole world becomes kaleidoscopic, and you go inward, by the way. It’s an inner trip, not an outer trip.