Is this this reason to be upset?

Okay, well me and my boyfriend were talking about spanking (we're both males btw). Basically he was telling me how he was into it and liked being spanked and that he spanks himself. So this is all new to me and im into it because it seems really kinky and etc, so im asking questions. I ask him when does he spank himself and etc, and so then i ask "How do you spank yourself?" Because i at least know there are items people use to spank themselves are another person, and keep in mind that im aroused and into it, and then he goes "Lmfao, really? That's a stupid question. I use my hand". And every form of arousal leaves my body and I just felt insulted and embarrassed. I just felt vulnerable since i was exploring his kink and he made it seem like i was an idiot, so from then till now i've been sort of silent with him, and he seems clueless about what he could have done wrong, but i don't want to argue about something he said hours ago, yet I just still have this anger about it. What should i do?