Sasha is a dom. One who takes a more cerebral route towards her conquests, but a dom nonetheless. And when you're as hardcore and practiced at it as she is, you often tend to dissociate the good feeling of domming a person from that person's characteristics. Basically, if she can push you around, it will make her sploosh a little. Maybe not a lot, but at least a little bit.
In absolute terms, I think you could call that being bi, but I don't believe that's accurate. If it came down to which body shape she found most appealing, that would be a different discussion altogether. But as of yet, we have seen no evidence of her lusting after anyone in particular, and we may never know.