I need help describing the sound of a SET to a friend in English.

It’s like cozying up next to a warm fireplace on a brisk evening. It’s intimate, present, seductive, and memorable. 

SET amps focus on current and the first watt. The tubes add the glow and bloom to the music, and rectification and quality transformers add the push and sag to make it very involving and also softer and more pleasing to the ears.

How can "the sound of a SET" be best described sans system context and the execution/implementation/design of the SET components within that system?

Let your friend listen to a system with SET amplification and come to his/her own conclusions in comparison with his/her prior references.

A real experience versus a cognitive exercise.

In a system that has synergy, a SET is dam good.

@dekay  Listening to 'K' by Kepa Junkera Urraza right now. Thanks for the recommendation. I spent a few months in Basque country. It's bringing back memories!

I once listened for an afternoon to two of the very expensive SET amplifiers made by Audio Note, original Kondo designs from Japan, not the UK imitations.  One was the Ongaku (around $70,000) the other was a Kegon (more than $100K) up- and downstream components were exactly the same, same program material too. (Speakers were also very expensive Audio Note, made for these amplifiers to drive.)  Both amplifiers sounded very good, but they were also very noticeably different sounding, one vs the other.  I concluded from this demo that the best (or these most expensive) SET amplifiers represent a purchase that one must make with the consciousness that you are buying colorations that you had better like. So, you are not doing your friend a service to just recommend an SET amplifier unless you are intimately familiar with what he likes and that his speakers are suitable.  Into the wrong speaker, any SET will sound like crap.