When I had this certain non-live-in BF we'd need to schedule our time together, mostly because of conflicts on his side, and try to plan ahead those nights he could sleep over (he had a nearly-adult adopted son living with him, so sleepovers weren't possible at his place). A sleepover was synonymous with sex, but we wouldn't state it that way. Rather, we talked in terms of his "staying over" or "staying the night." One didn't need to draw a picture.
Or else we'd talk about having dinner at my place, and/or watching a DVD with champagne and chocolates, which in turn was usually a prelude to sleeping over, or at least a romp in my bed before he had to get back to his place. But never did we say "when are you coming over for sex?" or anything like that.
And while he kept a shaving kit & toiletries in my bathroom, he still needed fresh clothes in the morning, which he'd either leave in his car outside in a gym bag until needed, or if he brought them inside when he first arrived, that told me all I needed to know.
As for my late & current partners, no overt scheduling of sex. On the contrary, I like to be unpredictable and unexpected, at least from his perspective. In reality I often plan ahead quite carefully, setting the scene as best I can, choosing what I think will be a good moment. But he imagines it's spontaneous, when it rarely is, since I want everything in place & perfect for him, no stumbles or mishaps.
Needless to say at our ages we're not having sex every single day anyway (is that a TMI?), but neither is it an annual event. So I have the luxury of a little time to pick my moment & place. And also, I hope, the good grace to defer if it happens that he's not in the mood (I know, you're wondering how that could be, someone not in the mood for sex with ME?)