Talk Time - Bonding or Bane?

When I fly solo at night with the kids, they lobby (incessantly) for "talk time" once the story is over. After a negotiation for a time limit, I turn off the lights and leave the two of them to their own devices. From down the hall, it sounds like a mixture of bad karaoke (oxymoron?) and a hyena convention. What the heck are they talking about that's so damn funny? He's 3 and she's 7, I can't even imagine what they're talking about in there. But, am I winding them up or winding them down? Who knows, but I have found that the potential loss of "talk time" seems to carry an incredible amount of importance.