She was relieved that Rena took to the idea. The woman could have said that blowing bubbles was overly childish. Then Molly would have had to argue the point. And she really wasn't up to spoiling their day over it.
Molly nodded. "That looks about right. So long as you can tilt your head over enough to put your face about this" she held up to fingers to indicate an inch or two, "far."
Molly waded over to sit beside her. Well, not quite beside her. Molly had to go a little further towards the shore to find a seat shallow enough so that her head stayed above water. She settled so that she would be in Rena's line of sight.
"Right then. This is what you do. You put your head in the water, like this." Molly dunked her head just enough so that her face was submerged. Her ears didn't even go under. Then she lifted her head back out. "And while you do, you breathe out through your nose. The really important part is to remember not to breathe in again until you bring your head back up. Do you want to see?" Molly could demonstrate first. That would give Rena a little longer to get used to the idea.