I did this for 10 mins which felt like a lot. As soon as I stopped, my penis went flat within 1-2 mins then I started again. Breathing helped it go down
I tried to simulate different positions. When i was laying down, it was easy, but when i changed to a doggy style position it was harder to keep the arousal in control. Good exercise
The same happens with me
Had to stop a few times at first but after that breathing excecercises really helped