A WhatsApp booking is a reservation agreed in writing in a message thread, at whatever hour the guest happens to write, with Telegram as the alternative.
Nobody at the house expects a phone call, and most guests are relieved to hear it. A reservation is made by message, on WhatsApp or on Telegram, from wherever the guest happens to be: the back of a taxi, a hotel bar, a bed with the curtains drawn. The booking line is listed on the booking page.
Three facts decide nearly everything. The part of the city, the length from the ladder and the time. A line such as "near the Museumplein, two hours, from half past eleven tonight" can be answered on sight. The name of the hotel is not needed, and the room number belongs at the end of the exchange rather than the beginning, as the journal explains in the room number goes last. A preferred therapist, if there is one, can be added.
The reply says whether the woman the guest named has that hour free, or which women on the roster do if he named nobody, and it quotes the figure; the choice of name stays with him. If the reservation carries a deposit, the amount and the payment details are written into that thread once the hour is agreed. That thread is the only source those details ever come from. A message from another number or account asking for payment on the house's behalf should be ignored, however convincing it looks.
A hotel evening is full of small facts that go wrong when spoken aloud: a street name with three consonants in a row, a tower with two entrances, an extension number mistaken for a room. In writing they are fixed, and both sides can scroll back to check them. The thread also serves as the guest's own record of the price, the deposit and the balance still due.
Guests who prefer brevity can keep the exchange very short. The house needs enough to arrange the visit and nothing about the reason for it.
Tonight
Name the room, the hour and how long you would like her there. The reply comes back in the same thread with who is free.