how can i be more bold

I am super comfortable around my boyfriend but i get very nervous when we do stuff. On a regular day i’m very quiete and kept to myself but around him i’m more outgoing and talkative but when it comes to doing stuff I go back to being quiete and kept to myself. I love doing stuff with him but I want to be bolder and be able to not care about anything and let go. For example I get to shy to initiate it. I also feel like in past relationships its always been the guy to start it without a question but I can tell my boyfriend now wants it from me. Any tips for letting all that behind.