Tired and he's horney... on the phone..

We talk every night, usually at least for an hour.  The hornier he is, the more he pushes sexual ideas and concepts.  Now, to be clear, I enjoy sex, and I'm not opposed to trying new things... and what he is talking about isn't exactly "on the edge" kind of stuff. I am ,however, the product of a conservative, modest, midwestern upbringing, and actually discussing any of this is hard to start with. Add on top of that a 12 hour day at work and being up past my bedtime, and he want's to discuss how I should enjoy a good swat on the ass because it means he's crazy about me and wants to jump my bones.... IN THE GROCERY STORE!  I'm NOT ok with this concept-  some things are not meant for public consumption, and whether or not I like a swat on the backside, it doesn't belong in public.  He's trying to nudge me towards releasing my inner sexy me.  I appreciate his efforts, but I actually had to stop him last night and ask him if he is ok with me staying me... because when he pushes the issue as he did a number of times last night, it has a narrow range or responses.  Either I take a deep breath and remind myself he thinks he is returning the favor for me making him a better man(which he did all by himself), or more likely I have a much more negative response, including anger, frustration, a desire to yell, and/or complete shutdown.   The thing is, I understand that he believes there is this wild sex goddess buried inside me, and he wants to help me find it.  It isn't going to happen over the phone, or be like a light switch turned on.   And I DIDN'T make him a better man (his words not mine). I didn't try to change him, he changed himself.  I don't think he quite understands that.  I'm positive he doesn't understand it at midnight when he's horny, I'm tired, and we're on the phone.