I was always open to sex of whatever kind on first dates (or any dates, for that matter).
I always just went with the flow, and tried to read the vibes my date was sending. If I was attracted to her, and she seemed attracted to me, I never hesitated to go down on her, or to be the first to go down. Of course, I'm pretty orally-fixated!
It always just depended on how attracted we were to each other and how comfortable we were with the pace of things (mainly how comfortable SHE was, since I was usually down for whatever if I was attracted).
I've always just gone along with the flow. Usually, I've been able to tell if my date is pretty sexual by the way she takes care of her body, ex... if she is fully shaved, trimmed or natural. I've learned that the more a woman is focused on what she looks like, the more she is interested in going with the flow also. Which usually means both of us going down, or I will atleast go down on her if she seems interested. I will atleast try, and if things are going well, I will suggest 69, then we can both get into it. I'm a very orally fixated person also.
I pretty much go with the flow. Oral is a huge part of foreplay with me. I know that some females are a little reserved due to fear or rumors or reputation but I seem to have been blessed with an "I don't give a shit" attitude when it comes to others opinions of me. Call me a slut because I give head/sleep with guys on a first date...I really don't care lol