What to expect
Start with two nights in Iquitos: arrive, spend time in the city and optionally visit Allpahuayo Mishana. Day three takes you to Nauta, where this example includes a night. Days four and five are for the agreed Pacaya Samiria stay. Day six is a return travel day, not a hidden extra excursion day. Compare this outline with the offered boat route and agree the overnight stops and return journey before booking.
How it fits into a journey
Only book a day-six flight once the provider confirms the complete return journey fits; otherwise fly the following day.