Sorry - just catching up with the threads. Ah yes, Coco flopping. Yes, as previous threads indicate, it is known as a DBF. As the name suggests, it's quite reminiscant and rabbits devised this tactic to scare the living begeeezers out of us hoomans by pretending they've just collapsed. It is perhaps worth mentioning that it's important to monitor all other signs of your bunny when performing this act - ie still breathing (chest going up and down) etc. No visible signs of injury etc.
If there's nothing of the above, then you have a DBF - which in bunny world, is utter contentment and happyness. The reasoning is, that rabbits don't naturally show their tummies - it's ultimately their vulnerable area so to expose this is a sign they are comfortable and trust you. It's scary the first few times, then you get used to it and it's kind of sweet.
Rabbits have a range of emotions - but because they are non vocal, it can be tricky to pick up on them. It's a learning curve. Coco (along with probably every other rabbit in the world) will hate vets visits - they just know. And so, on return, they'll be sulky. You've taken him somewhere against his will and for that there's a price to pay. If Coco sits with his back to you, you've upset him. He will still be looking at you even though he is facing the other way. But for now, you are the lowest of the low. Flicking his feet at you is another way to demsontrate his displeasure. BUT - and this is the best bit, they usually don't sulk long and generally speaking, food (treats) will bring them out of the sulk. You just have to know that in Coco's world, he's top dog and you're not. You're there to serve him.
I'm pleased he's now eating again - he'll likely be fine by the morning and every day he's with you he's growing in confidence and trust.