Sounds in the night

I woke up to a squishing rhythmic sound...

I was facing the wall, with my back to my boyfriend. He cannot sleep lying down completely, so he sleeps in a sitting position on an armchair next to bed. 

At first I thought the sound came from outside the room, maybe from the living room, where the cats are... 

But then I realized it was coming from my boyfriend...

I laid perfectly still, pretending I was sound asleep, wondering if he was pleasuring himself to some of my photos, or maybe even to the sight of my uncovered bottom... But there was a high probability that one of his bitc- I mean, cyber girlfriends, had sent him some nudes and he was reacting to that...

Either way, I didn't interrupt. After a while, he finished, cleaned, and finally I heard him snoring. 

It took a while for me to go back to sleep again... Maybe I imagined it?