He's Actually Starting to Carry the Canter!

Rogo's transitions into the canter have been pretty good for awhile now - reliably picks it up quietly from the first ask and gets the correct lead. The problem has been keeping the canter, but today he got it! I asked for the right lead and cantered around the end, down the long side to E, did a respectable 20 m circle, cantered out of it and asked for a trot, which I got. Then crossed the diagonal and did the same to the left which he also did well. The left circle wasn't quite as good as his head was turned in too much to be straight on the bend, but it wasn't terrible. He went from not doing it at all (as recently as Tues. it was getting better, but not near this), to doing the whole thing, really well both ways, in one day. I'm not complaining, but what's up with that?
I've been doing lots of trot circles to work on balance, and longing a lot at the canter, so maybe he just felt confident and balanced enough to do it. I did just lightly touch him behind my leg with the whip a couple of times to encourage him, but it used to be that if I tried to do that for encouragement he'd stop and buck (more of a resistant 'bump' than an actual buck) or race without much 'steerability', so I backed off trying to force it and waited for him to be ready (sometimes wondering if I should be pushing harder but with both Joan and Cheryl telling me to let it develop). 
Oh la la!!! I'm over the moon. I have an actual real horse to ride!!!!!