overall, I like the idea (and the video link, too).
The only small difference I would make is: the guy seems to be pretty young (around 18, I guess?). I think most people in a nudist camp understand that it is natural that a young guy receives an erection when he sees nude women. So they just ignore it.
However, Mom can't ignore it. She is a little bit embarassed about her son. She hopes the erection will go away alone, but after a few minutes, his dick is still rock hard.
So during a break, she leeds him to a small cabin to talk with him about his feelings/erection ... in the end, she takes care of it ...
Oh, but I just had another idea (inspired by the video):
The whole interview in the camp is over, everything worked flawless, without an erection. Mom and son have some time left, and the camp people invite them into the pool. Mom is laying on a lilo, floating in the pool. Her legs are spread wide. Son wants to talk to Mom and so he is swimming over to her. When he stands up, he is right between her legs, having a great view at her pussy ...
"We have done so much, with so little, for so long, that now we can do almost anything with nothing." - Dave Marcis