I noticed that there were some romance scenes had a variant of your party members wearing only underwear along with fully clothed, how do you get that variant?

If you remove their armor before initiating the scene...

Is that all? Because I found a video where that’s not the case https://youtu.be/0q9uULlMol8

Start at the shadowheart invitation tab that starts at 18:51

the video is not continuous

Well I wasn’t sure

Still, I didn’t think they’ll be briefs

Idea for a new topic:
how to remove underwear from a character?
Right in the middle of the tiefling camp. Sooner or later, someone will create a topic like this