Basically one day in the Sanctuary* (I figure they've been closer than they would have in the warehouse Hideout) someone notices that Rebecca's moving a little differently when "listening to her music" than usual, so when her back is turned... YOINK!
... and then that someone then freezes when it's the sound of a low moaning, or whimpering, or gasping or other muttered sounds of sex coming out of the headphones they're holding... and the voice is one of them!
TL;DR: Naughty Rebecca's been listening to the audio equivalent of a sex tape of one of them (possibly herself)... the context and whatever happens next is up to the writeanon, be as serious (breach of trust anyone?**), smutty (maybe they decide to punish her?), or crackfic as you like!
* There's something about the dynamic in Brotherhood that leads me to believe that the villa's where a lot of us anons are setting our OT4. ** For this reason my HeadCanon!Rebecca refuses to let ME have it be anyone except her own voice so that only she has to deal with the embarassment, but writeanon the choice is yours.
What's Rebecca listening to on those headphones anyway?
... and then that someone then freezes when it's the sound of a low moaning, or whimpering, or gasping or other muttered sounds of sex coming out of the headphones they're holding... and the voice is one of them!
TL;DR: Naughty Rebecca's been listening to the audio equivalent of a sex tape of one of them (possibly herself)... the context and whatever happens next is up to the writeanon, be as serious (breach of trust anyone?**), smutty (maybe they decide to punish her?), or crackfic as you like!
* There's something about the dynamic in Brotherhood that leads me to believe that the villa's where a lot of us anons are setting our OT4.
** For this reason my HeadCanon!Rebecca refuses to let ME have it be anyone except her own voice so that only she has to deal with the embarassment, but writeanon the choice is yours.