Well, first off was realising that I should reframe my thoughts on it. "Attention barking" makes it sounds like it's "bad". Instead, I started to look at it as simply communication: she was telling me she needed something. In the same way as I wanted her to ask when she needed to go to the toilet, she was just telling me when she needed interaction.
So, first off, work out what triggered it. For her, it was quite straightforward. She needed interaction after waking from a snooze, and at regular intervals throughout the day. So I worked on incrementally increasing the time she could manage without interaction, in exactly the same way as you build duration with anything - slowly, and trying not to push too fast, too soon and trigger the unwanted behaviour. Most importantly, when she
did bark, I gave her that interaction. Reframing it as a NEED helps to get through the brain fuzz with this ("aren't I reinforcing the bad behaviour?"). My puppy NEEDS the toilet, but is barking to go out... would I make the puppy wait until she'd stopped barking? Only if I wanted a puddle! The NEED doesn't get any less by denying them the thing they're asking for. She wasn't "demanding", as many people label it; she was just asking in the only way she knew how. So, try to prevent the behaviour happening, but appreciate that if it does, you've just asked too much.
The toilet training analogy is really useful, because, yes, we are clearly running the risk of reinforcing (strengthening) the behaviour, but the same is true of a puppy peeing on your rug: that is intrinsically reinforcing, because it relieves the discomfort of a full bladder. Does this mean that a puppy who pees on your rug will continue to do so ad infinitum? No, it means you need to ensure you become more aware of the triggers and get the puppy outside BEFORE she pees on the rug. And you have to make that experience (peeing outside) so much MORE reinforcing than just voiding where they want, so they start seeking out the "outside". So you're going to train your dog to start seeking out the behaviour of asking with the chin rest (or whatever), because it's more reinforcing than barking. And, of course, just as a puppy's bladder strengthens as they get older, so too does their ability to go longer between interactions with you.
I'll say right now that I didn't necessarily intend for her chin rest to become her "please", but what I did do is ensure that
every single time she approached me with an appropriate behaviour, I would give her attention. If she brought me a toy, I played with her. If she nudged me, I played with her. If she stared at me, I played with her. Even if I didn't have the time for a long session, I would play for thirty seconds or a minute. As a happy coincidence, during this time we were working on proofing chin rests on my knee in training sessions throughout the day, so she was getting loads of reinforcement and interaction for that one behaviour. One day, I got the chin rest while I was working and without me asking, and, because it was something I was already working on, she got a huge party for it. She's the queen of single trial learning, so she decided from thereon in that this was something that worked for her, and she's done it ever since. She also transferred it to asking if she can come up on the sofa or many other things. It's a great behaviour, because she can really target the thing she wants and use her very expressive eyes to stare between it and me
It's certainly something I will train with purpose in the future.