How do I approach my bf about using an extension?

So I want to preface this by saying that his size does not matter in our relationship. The sex we have is good; I'm just wanting to explore.

I've been with my boyfriend for a few months now, and we're both very happy. We also have sex a lot, basically every time we are together. He doesn't have a lot of kinks or fantasies, but he isn't against it. I'm someone who definitely has more and wants to try some stuff. We have talked and he isn't against toys and doesn't compare himself to the toys that I use. The thing is, he is on the smaller side down there. It isn't a big issue, but we are somewhat limited to positions we can do and sometimes I feel like I would like to try something bigger.

I've thought about trying a penis extender, but I'm not sure how to bring it up to him. He is very chill and understanding, but I don't want him to think that he isn't enough for me or that I don't enjoy the sex we have as is.

Has anyone else been through this? If so, what did you do?

His size isn't a deal breaker for me, and if he is against trying the extender, I'm okay with that. My relationship isn't based on sex at all. Just wanting to try out something bigger from time to time, and dildos just feel too inhuman for me at times.

Thanks?