In Japan, most children are taught to "submerge the shoulders for a while, counting 60 seconds, before leaving the bath".

When they grow up, the bathtub in a normal household is not big enough to submerge the shoulders in, but in public baths or onsen, they stretch out their legs and submerge the shoulders in the bath.

Submerge your mouth and blowing bubbles is bad manners, Don't do it in public places.

if necessary, add "bare shoulders" to negative prompt.

Finally, I found out that in Danbooru, there is a tag "mouth submerged", so I should have used a trigger word "shoulders submerged", but it's too late.

P.S. I also found large breasts can cause confusion, so lora doesn't work so well lol.