Outcall to the room you already know
Outcall means she travels to the hotel room or apartment where you are staying; the house keeps no premises, so there is no address for a guest to visit.
Outcall is the only way this house works. The therapist comes to the address written in the thread, and the guest stays in his own room. There is no studio, no flat kept for the purpose and nothing a visitor could be directed to.
Why regulars value it
A returning visitor usually knows his hotel well: the lifts, the side entrance, the room that gets the evening light. Outcall lets the evening happen on ground he already understands. The only work is to write down the floor, the room and anything about the entrance, which the guide to keeping one thread covers.
Where it reaches
Central Amsterdam, inside the arrival window of forty to sixty minutes. Schiphol and the airport hotels on request, after the journey time has been settled in writing. Nowhere beyond those.
What a room needs
A bed with some space around it, a door that closes and, for formats that use the bathroom, a shower that works. Two therapists or a couple need more floor than one guest alone.