The good lads of Yellow Magic Orchestra may have appeared rather stoic in the promo shots when I first got to know them, but the longer I did get to know them, the impression seeped through that they didn't take things all that seriously. They had some good fun with other genres through technopop such as surf rock ("Cosmic Surfin'") and R&B ("Tighten Up"). And of course, there were the music videos...the one for "Kimi ni Mune Kyun"（君に、胸キュン。）had the tongue so much in cheek that it threatened to break through.
Another song that struck me as being a bit "on the lark" was "Multiplies" from the album of the same name (1980). First coming across it via their BEST album, "YMO GO HOME!" (1999), I had thought with that title, there would be something very seriously techno about it. Instead, my introduction to it started with the theme song from "The Magnificent Seven" followed by what sounded to me like a pretty uptempo version of a spaghetti western (known as a macaroni western in Japanese) soundtrack. However, I read on the article for the song on J-Wiki that YMO fashioned it as a ska tune out of The Specials' playbook.
The same article noted that Haruomi Hosono（細野晴臣）noted that although Yellow Magic Orchestra was to be credited for the music for the track "Multiplies", a bit of consternation percolated considering the source material. Now, the song has Elmer Bernstein and/or YMO being bandied about in the credits for later reissues.
In any case, hearing some of the vocal effects by Hosono and gang, I figure that there was some of that button-down fun going on in the recording sessions. It plays like background music for a montage scene in a Japanese comedy.