Kind of an odd way to just hang out in your room, but my theory is that his boyfriend came in while he was playing Rhythm Heaven and they started flirting.
I've had this line art done for AGES, you can kinda see the age on it because my style has changed a tad. I really missed drawing cute room settings like this. I also wanted him to have a bulge but it doesn't quite make sense at this angle. ┐(￣ー￣)┌