That sounds perfect. Love it. Of course, when Lilly starts to fall, mum reaches out to grab her, but only succeeds in tearing off her bottoms (in a totally illogical way that defies all laws of physics). We still need her butt smacked a few times though, you can't let naughty girls like that get away with bad behaviour.
And she was obviously planning on getting caught in the first place, so we can't disappoint her.
So up she comes out of the pool, bare-bottomed and dripping, and since that looks silly the top comes off as well. Now she has to take her punishment in mum's lap, except those swats on her butt soon turn into something very different. Something that they both start to enjoy quite a bit.