I want to masturbate in front of my SO - advice?

So let me start off by saying my SO and I have a very easy relationship, sex is easy and amazing - there has never been an awkward moment. So now I'd like to try and masturbate in front of him and let him watch... I'm just not sure how to pull it off or get it started. I don't want to look like an idiot 😂 any advice??