Fingering him

So we’ve been together for about 6 months now. He’s finally starting to open up to me about what all he is into and what he likes sexually. Sex is always so good with us always has been. Last night I decided to explore when I was teasing and rubbing him, I wanted to see what he was comfortable with and how far he’d let me go before he asked me to stop. Well, he never asked me to stop!!! I ended up fingering his ass until he came so much it made me soaking wet to watch! It was very generic though, as I didn’t really know what he was into, so I just slowly fingered straight in and out.. and tips or advice for making this even more pleasurable for him next time? He loves his nipples played with, his balls sucked and rubbed, neck licked sucked and bitten...