Pai Slash (Boobstrap)

https://civitai.com/models/122085/pai-slash-boobstrap

There is currently a LoRA that does a similar effect, but noticeably with more anime/animation style and smaller breasts.

This is modeled on larger breasted examples. A strength of 0.5-1 works well. Some models don't seem to handle this that well, but most I tested, real or animated, worked well.

Keyword: paislash

Others: strap between breasts, seatbelt between breasts

See the author link above for details.