I’m going to post a link to a video below, but I’m warning you now: the video and lyrics are extremely NSFW.
Disregard the lyrics and focus solely on the instrumentation, the melody, the vocalizations. Pretend the lyrics are about hosting a garden party, if you like. But whatever you need to do, separate the lyrics from the song.
Once you’ve done all that - and ruled out “parody” - what genre of music would this type of song be? Sounds to me like where Beautiful Music and Vocal Jazz would intersect on a Venn Diagram, but I’m no music historian.
Sunshine pop is the best term, if we want to narrow it down to one genre rather than call it a blend of source inspirations. This particular song reminds me of the '60s group The Sandpipers more than anything else (especially with the vibraphone part). “Easy Listening” is also valid, since a lot of the now so-called Sunshine Pop acts ended up in the Easy Listening charts back in the '60s.
Incidentally, I’ve seen the Wet Spots live - they’re a very cute act!