She seems to have caught on to his plan.

"If I do it here a wave is going to hit me in the face." And if she does it a little deeper in, it will hit her in the ass. This is a problem.

But Clarisse is not one to give up easily. She's brainstorming. "Maybe there's a sandbar I could swim out to and do it there." That way she'd be in the water but out of the waves.