My boyfriend put my finger in his butt while i was sleeping

I'm posting in here because i do not want any shame or "eww" comments...

For 2 years I've asked here and there about fingering his butt when we play because honestly so many men say it feels good and from what i heard (correct me if wrong) but their "g-spot" is more accessible through their butt.

He let me do it one time but that was it. But when I'm sleeping, about 4 or 5 times I've woken to him putting my finger in his butt. He doesn't know i woke up each time because i don't want him to feel shame or embarrassed.

(One of my kinks is stuff being done to me while im sleeping...pls don't shame, i gave permission)

But my question is, could it just be a kink that he likes it when I'm sleeping and not when I'm awake? Or do you think he feels more shameful allowing me to do it when I'm awake. Obviously no one knows how he feels and I'll talk to him, but I'm wondering if anyone had any similar experiences. What was the outcome for you? How can i make him feel more comfortable opening up to me about kinks?

Like i said i know that no one here knows how he feels, so no need for those "we don't know ask him" comments i see all the time, I'm asking if you have experienced this and how you went about it