Bidar

Though I _think_ he's straight: but then my bidar isn't always running at 100%.

Bi people hang in straight places a lot, and given that you are also bi, they will probably stand out to you in an indescribable, nonverbal way. And that, my friend, is bidar.

Of course, not all bisexuals are recognizable, and many will easily defy the bidar, whereas others will appear to be bisexuals without actually identifying as bi.