Like, would something like this:
http://i103.photobucket.com/albums/m121/methodical_parabol/skittles.jpg
be acceptable, or not? I mean, it has all the necessaries covered, all you see is the butt cheeks. And that bottom could very well be a swimsuit bottom, let's not just assume it's underwear.
Even if it was swimwear op, your bed is not the appropriate place to go swimming. swimwear is only allowed on the beach/pool.
I was waiting to read this. QFT.
You never know, she could have a pool by her bed....
I'd accept it.
However, that picture would be rejected on underwear grounds.