But then I heard a familiar, haunting sound. The little guy started chirping - right on my lap! He continued for about thirty seconds, then took a deep breath and finished his serenade.
Like his first chirp, it was about 10:30 PM.
This is about the coolest thing I've ever seen with a guinea pig.
I don't think it's a private thing. When Spot chirped four years ago, I actually picked him up and he didn't stop... but stayed in a trance-like state for several minutes.
Winnie chirped last weekend and I was standing right there.
I wish we knew what was going on when chirping happens. Your description of his breathing makes me even more curious.