Ahoy, Aimee!
Thanks for stopping by the Moms Panel with your question.
I'm happy to hear you're planning to ride the awesome
AquaDuck water coaster when you sail on the Disney Dream in May! Unfortunately there is no "rider swap" option available for guests.
The line for the Aqua Duck starts on the pool deck and winds up a somewhat narrow staircase before entering the area where you board the rafts. There's really nowhere for a parent to remain in line and hold a child while the other parent rides and rejoins the line. AquaDuck is designed for Guests 42" or taller, and smaller guests will not be allowed to enter the line at the start point.
My advice is to ride the slide when the lines are shortest, either early morning or late afternoon/early evening. If you're planning for your little one to visit
it's a small world nursery during your cruise, you could always consider reserving some nursery time during the day so the two of you could relax at the pool or ride the slide together.
I hope this helps with your planning. Have a magical day! - Diane W.