Have been both on the giving and receiving end
In my earlier days, I ghosted my FB due to immaturity on my end. She took it well I believe as we bumped into each other a few years after and we caught up over a drink and talked about it. She's much more mature than me and forgave me for that. We still keep in touch every now and then, but nothing sexual except for some random dirty jokes now and then.
I have also been ghosted and like many said, being the receiver really sucks (which is all the more my admiration for the lady I ghosted).
Nowadays, I will normally just talk things through about what I find lacking. Some ladies will get upset (they will claimed I used them even though I reminded them that we both agreed on the NSA arrangements). I don't think there's a right answer, as it depends on the other party.
If the other party is mature, talking things through will definitely be the best.
If not, I will cut down the number of meet-ups and the meet-ups will not be sexual in any way (maybe just a coffee and bye bye). As a lady, you may also want to make sure that you don't go anyway too private/quiet, for who knows, that guy may turn violent if you finally broach it. I tried this on 2 ladies, and both of them got the idea that yup, the arrangement is deviating from what we wanted. One of them got it after just a couple of meetups in a cafe and it ended there, while the other also got it after about 4 to 5 dates, but tried to prolong it (I guess she started to be emotionally attached too, which is one of the reasons I wanted to end it as well). In the end it wasn't too pleasant though with her crying in the cafe and some bombarding of msgs after that for close to a month, but I had avoided replying her. We are now not in contact though.