When I'm free and in the mood I basically message any girls that catch my interest and do the services I'm usually interested in, just asking if they're happy to do X at Y. Before messaging I do a ctrl+f search in my sent folder to check I haven't emailed them before.
If I get a positive reply and am happy with their general attitude and profile, I hotlist them with a note that they're interested in X at Y.
Then when I'm in the mood for a punt, I'll draw someone from the hotlist and see if they're interested in it on a certain day.
Hotlist is pretty small (5 or so at the moment?) as of the few girls who catch my eye and do what I'm interested in, even fewer still reply. Maybe they think I'm timewasting not asking for a specific day, but it can take forever to track down a decent girl and wait for her to respond, that I think you need to have it all worked out in advance.
Post punt if they're shit they get taken off the hotlist, never to be seen again.