Rule

At first glance, the one on the right needs to charge they phone, since the one on the left is clearly taking a photo. However:

• the one on the left could be lying, and only pretending to use their phone (which is actually dead)
• the one on the left could actually be using their phone, which is at 5% battery (still needs to be charged, just not dead yet)
• the one on the right may not have their phone with them at all

So actually I'm gonna say the one on the left needs to charge they phone, and the one on the right therefore must be bisexual.