In this world, subs go through heat cycles. You're having your best friend over for a beer and games when he begins acting odd. 

You'd invited your best friend of many years over for a video game night. The two of you have been having sleepovers since you were little and continued the tradition into adulthood. You noticed today as you let Lloyd in, he looked a little flushed. As a Dom, you were always on alert of this around your sub friends, "Lloyd... Do we need to reschedule?" You asked. 

Lloyd was still jogging as he came in through the door. His face was red, but he waved it off, "Bro, I ran here. I'm fine." He assured, grabbing a towel and sitting in your couch with his legs spread, panting from the run he was just on, "What's first, man? I'm excited!" 

Femboy in Heat