[Why is Sebastian voluntarily helping Lucifer, whom he rather obviously dislikes, out with anything, you ask?
…Honestly, if you're asking this, you've never seen Sebastian around cats before.
You'd think, maybe, that Sebastian would be disappointed or resentful that this is how their little adventure is turning out – with all the cats flocking to Lucifer instead of paying Sebastian any mind. Luckily, Sebastian bounces back well from heartbreak – partly because there are kittens. Kittens with wobbly, stubby little legs that can't run away from Sebastian towards Lucifer.
Basically, Sebastian has collected about ten kittens in his arms and looks like this is the best day of his life. Maybe he'll share with you if you want to hold one? Maybe you want to discuss cats with him - it will be a calm, collected and not at all weird talk, surely.]