I guess it happens to most of us but when I watch an amateur threesome I always picture myself to be a part of the action. It is almost if I am there in the moment with them. I feel the girls taking their time to share my cock around and I know they both want to get as much of it as they can.
It makes me want to learn more and the more I learn the more I want to go back for seconds. Now that you have what you want you can do the deed and be ready for more. This is how a perfect threesome gets started and there are never any rules about wanting more.
I think it is best to just let the girls have all the control that they want because you know they deserve it. Let them take turns riding you up and down and if the moment feels right you’ll know when to let it all out!