I watched it tonight to make sure and you are right. She was lying on her back, Thorton was kissing her stomach. She had a black bra on for part of the scene but was briefly without her top. I only have my VHS copy, never saw it at the movie theatre.

I just verified this, I have it on my old VHS copy (yes some people still hold onto their VHS tapes.) Wonder if there is a way for me to post it to youtube. But yes this is true. I met the director at a flim festival once and wish I knew, I would have asked him about it.