how to initiate sex

can someone give some tips on how to initiate play time lol, I guess you could say I'm "shy" when it comes to doing this bc I just feel awkward but I'm not a general shy person, very comfortable around my SO. He wants me to initiate it and take control but everytime I picture it in my head it goes so smoothly but when it's that time I just lay back and wait for him to do something. Tips?