No worries :D What scene are you talking about specifically? Because generally, the music volume works as intended, even during spicy scenes (Just tested it to confirm).
I think there was one scene where I had to work around renpys music channel limitations. But if that ended up being a problem, I might have to re-adjust. So please let me know what scene you mean so I can take a closer look at the code! :)
Ah, I just checked the scene and know what you mean! Here's what's happening: I sync the slam and impact sounds during spicy scene directly onto the video itself. This way, I can guarantee that these won't desync if you loop the video for a long time. But what happens is that Renpy, the engine, says the music channel selected to output video sounds is the music channel. So that's why you had to turn up the music volume to hear the impact sounds. And unfortunately, there isn't a super easy solution. Renpy only has Music, Sound and Voice channels, so choosing a different one will only push the problem onto either the moaning channel or the ambience channel (beach waves for example). I'll put it on my list of things to look into though. Thank you for letting reaching out and I hope I was able to shed some light onto it! :)