I got a new pair of headphones today, and since every pair sounds different, I've been listening to all my favorite songs to see if I can spot things I haven't heard before, sounds buried in the mix and stuff like that. Anyway, after rewinding and playing around with different EQ settings for about 30 minutes, I think I can finally tell what the background vocals in the chorus of You Are Still A Mystery are singing:
Tell me your secrets... Don't try to hide...
Give it to me straight, now... What you keep inside...
Need a little hand, now... Don't play with me...
Gotta find the key, now...
You are still a mystery.
The first part has been confirmed by Andy Paley in this interview:
http://www.rockcellarmagazine.com/2013/09/04/beach-boys-collaborators-stephen-kalinich-andy-paley-interview/The rest, I'm pretty sure that's what they are singing. Like, 95% sure