He and I have hung out without flirting or anything once but we text (mostly) every day. We started talking about how he likes bjs and I said I liked when a guy went down on me. We toyed with the idea , and hadn't mentioned it since. Then we kind of brought it back onto the table and we are deciding to do it but very secretly since we also have a rather large number of friends in common (entertainment business) 

So we are wanting to do it because neither of us had any action for a while, and keep it as Fwb. But promise ourselves that we will keep our friendship how it is. 

I'm scared of being nervous etc. (It's been many years for me) 

Can I get some thoughts and opinions? 

I do have an IUD, and he will be using condoms.