I guess out of the few things Tom Kane excelled at in his writing, his use of adult humor was more... I guess clever would be the alright word to use. Things that were spoken like "the very tall grass" and "full moon" really seem more like what kids really wouldn't understand before they grew up unlike the first movie where Paddy pretty much flat-out said that Humphrey and Kate were brought out to have lots of sex, then Humphrey's expression afterwards sealed the deal. That got chuckles out of me after watching it the first few times, then it just felt like "of course."
Yet I still manage to get a laugh out of Humphrey waking up Kate in the den and the first thought Kate brings up is a little nighttime rendezvous.