
Bowing is a part of Girar tradition there's nothing humiliating or kinky about it.
That's totally fine for Llava, as he's naturally quiet, pietic and polite young man.
Ke's a mocking bird and a clown, so I suspect him comically sticking his ass up into the air and making a monkey face so only Llava could see.
There's a chance, though, that he is not aping in front of Llava too much.
Not to hurt his feelings. It's always been love, you see.
(Nevertheless, it's pretty hard to hurt Llava's feelings at all ;)