Well its been discussed over and over again from other threads so I thought I make one to discuss it here. Just what exactly is it that she flashed in front of the bandits who were keen on sharing her amongst themselves in a orgy party?
The possible outcomes have been discussed and these are some of the things we were able to come up with.
Maybe her internal organs are showing from the wounds she hasn't fully closed off from her last battle? (Somehow I doubt this because she's not the type to get damaged that badly even from a fight with the former number 1 of the organization). Others have came to the theory that there is something on her tummy that was implanted (yoma implants) which looks horrifying, this is somewhat more believable although... have we seen any of those from the naked bodies of claymores so far? Nude Ophelia's top half suggested no such thing and Clare's backside when she was told to go bathing by Ilena didn't show much of anything at all to prove she's been implanted something horrid looking. Its debatable but I personally thing this isn't it either. Maybe it was a horrible scar that looked painfully devastating to look at which only Teresa had? this is more believable for me I think, although the question then rises how and where did she acquire such a scar? This is the invincible Teresa we're talking about and if she did recieve a wound like that during battle would it not be easily healed without a trace using her Yoma powers? There was even a random joke which I consider a possiblity in that maybe she bares similarity with the japanese horror movie character Sadako and shares similar bodily features between her legs. While I think it could possibly have been a turn off to most bandits there were alot of them and I'm sure theres bound to be one or two who has questionable tastes.
So then without me writing up an essay do discuss your theory on the matter.