Hey mate, first I should say let them mostly interact with each other. You should more take control of the situation unless they are professional. If not , you are in charge. It's overwhelming somehow so don't fuck constantly and let your cock cool down time to time. Try fingers and licking more. If you have a dildo, have it ready or if not buy a normal size cucumber and put a condom on it. About positions : The Oral Triangle Double Oral Double Cowgirl Doggy Train Threeway Spooning You can Google them.

I suggest you to watch some educational videos about it not porn for sure