Caught my bf (23M) jerkin off to me (21F) on FaceTime…advice?

So… I noticed the camera shaking so i suspected it and the when he suddenly needed to go to the bathroom I could tell what he’d done. we have been together for 4 months now and long distance for 1 and I know we both have a high sex drive but really….without saying anything to me. I had just woken up and was in a sports bra and joggers so even if that had turned him on…I understand we’ve been apart for a long time but I’d hope he’d at least ask me for consent or say something and not s just start jerkin in front of me. I wonder if anyone else has any advice or opinion on this? maybe some advice on how to bring it up in conversation or if this is red flag etc? Thanks