Outcall, for a traveller who cannot leave the stop
Outcall means the therapist makes the journey to your room, at an airport hotel or in central Amsterdam, since the house keeps no premises of its own.
A passenger on a layover has a boarding pass, a cabin bag and a fixed number of hours. Going somewhere for a session is rarely realistic; being visited is. Outcall is the arrangement where the therapist is the one who travels, from wherever she is to the room where you are a registered guest, and the house works in no other way.
What that rules out
There is no studio, no reception room near the terminal, and nothing inside the airport. A lounge, a gate area or an airside sleeping cabin is not an address a booking can be made to, because a visitor cannot reach it. The session happens behind a door you opened with your own key, and nowhere else.
Two kinds of journey
Inside central Amsterdam, she is at the door forty to sixty minutes after the hour is confirmed. Schiphol, Schiphol-Rijk and Schiphol-Oost are served by arrangement: the journey time is agreed with you in the thread before anything is fixed, and half the fee goes ahead. The difference lies in timing, never in the rate; an hour costs EUR 180 at a runway hotel exactly as it does by a canal. The layover entry explains why that timing matters so much between flights.
What outcall asks of the traveller is small. Give the hotel and room number accurately, keep the phone on, and mention in the thread if the lifts need a key card. The booking page lists the rest.