The couples order almost always arrives mid-break, and almost always from a suite. Notes on why the room, not the occasion, decides how it goes.
There is a message the desk can recognise before it is finished arriving. It comes in the early evening, from a canal-ring suite or a tower's executive floor, and it asks, with slight disbelief that this is a thing that can be asked, whether two people can be massaged at the same time, in the room, tonight. The answer has been yes for years, and the booking it starts is one of the most pleasant this rota runs.
Guests assume the occasion is the important variable. It is not; the room is. A couples session is a small piece of staging, two working stations, two therapists moving around them, towels and oil in two circuits, and staging needs floor. A junior suite swallows the arrangement whole. A generous double manages once the armchair concedes its corner. The occasion, whatever it is, takes care of itself the moment the logistics stop being visible, which is the desk's actual job on these bookings.
Two therapists on one booking are not two separate dispatches. The desk sends women who have shared a room before, Sonya and Tina have run more of these together than anyone else on the rota, because the pacing is the product. The two sessions begin as one visit, run side by side at whatever registers the two of you asked for, and are steered to land within the same minute. One of you finishing ten minutes early, sitting up, reaching for a phone: that is the failure mode, and pacing is how it never happens.
City-break couples book the two-hour version more than any other, generally for the middle evening of a three-night stay, the first night belongs to the restaurant, the last to the packing. The room is warm, the second station is folded away before you have finished noticing it existed, and the rest of the night is still yours, which is the quiet advantage over any spa: nobody has to get dressed and walk anywhere afterwards.
One line of advice, offered from experience. Say at booking who wants what, firm on one side, slow on the other, silence here, conversation there. Couples tend to average their preferences when asked together, and an averaged massage serves nobody. The stations are separate precisely so the preferences can be.