this is a really weird question, so i’m going to preface this by saying ogeretsu tanaka- the author of the manga- wrote yaribu as a joke and pretty much had nothing to do with the making of the show. there’s close to zero information about who and why they made the song or lyrics. i truly and honestly don’t think it matters, though.

as a japanese speaker, i can assure you there really aren’t any hidden meanings or much to the song beyond sex/kinks/etc unless you’re wanting to count the very minor character development w kashima and toono becoming okay with sex at the end of the song. here is my summary of it: horny boys in sex club talk about being horny and having sex. virgin boy isn’t down w it and doesn’t want the orgy. another boy likes that boy and wants to protect him. they both end up fine with being horny. more sex talk.

i can’t think of any reason there would be more of a meaning, just look at the show... and to address your comment at the start, the only reason others might consider it disturbing is the open and explicit display of sexuality.